USMLE : Pathology Practice Test! Trivia Quiz

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USMLE : Pathology Practice Test! Trivia Quiz - Quiz


Pathology is the analysis of the causes and impacts of disease or injury. Pathology also describes the study of disease in general. When used in medical treatment, it means the incitation of processes and tests that fall under the umbrella of pathology. If you intend to know more about pathology, look no further than this quiz.


Questions and Answers
  • 1. 

    A 57-y/o man is brought to the emergencydepartment because of blurry vision, difficulty standing, and mental confusion. On physical examination the patient appears malnourished, he had diffuse crackles bilaterally, and on standing his gait is wide-based and unsteady. The patient’s friend, who accompanies him, says the patient “hasn’t been himself lately,” and is having difficulty remembering to do everyday tasks. Which neuropathologic findings are most consistent with this patient’s symptoms?

    • A.

      Atrophy of the caudate nucleus

    • B.

      Depigmentation within the substantia nigra pars compacta

    • C.

      Neurofi brillary tangles and widening of ventricles

    • D.

      No neuropathologic fi ndings

    • E.

      Symmetric lesions in the paraventricular regions of the thalamus and hypothalamus, mammillary bodies, and periaqueductal region of the midbrain

    Correct Answer
    E. Symmetric lesions in the paraventricular regions of the thalamus and hypothalamus, mammillary bodies, and periaqueductal region of the midbrain
    Explanation
    The correct answer is E. This patient presents with signs and symptoms of Wernicke’s encephalopathy (confusion, ophthalmoplegia, and ataxia) and Korsakoff’s psychosis (personality change, confabulation, and memory loss). This syndrome is secondary to thiamine deficiency and commonly seen in malnourished alcoholics. On postmortem examination, patients suffering from Wernicke-Korsakoff syndrome commonly present with symmetric lesions in the paraventricular regions of the thalamus and hypothalamus, mammillary bodies, and periaqueductal region of the midbrain. Answer A is incorrect. Atrophy of the caudate nucleus is found in Huntington’s disease, a disease of autosomal dominance associated with chorea and dementia. Answer B is incorrect. Depigmentation within the substantia nigra pars compacta is commonly seen in Parkinson’s disease, not thiamine defi ciency. Answer C is incorrect. Neurofi brillary tangles, composed of abnormally phosphorylated tau protein, are commonly found in the frontal and temporal lobes of patients with Alzheimer’s disease. Answer D is incorrect. Thiamine deficiency is associated with neuropathologic changes observed on postmortem examination.

    Rate this question:

  • 2. 

    A 41-y/o man visits his doctor because of increasingly painful headaches. CT of the head is shown in the image. If a biopsy of this tumor were obtained, what would the pathologist likely see under the microscope

    • A.

      Densely packed cells with halos of cytoplasm surrounding large round nuclei

    • B.

      Perivascular pseudorosettes with tumor cells surrounding vessels

    • C.

      Pseudopalisading tumor cells surrounding necrotic regions

    • D.

      Sharply demarcated areas of tumor cells located at the grey-white matter junction

    • E.

      Whorled pattern of concentrically arranged spindle cells with psammoma bodies

    Correct Answer
    C. Pseudopalisading tumor cells surrounding necrotic regions
    Explanation
    The correct answer is C. This patient has a lesion consistent with glioblastoma multiforme
    (GBM), which is the most common primary brain tumor and is characterized on CT by a
    serpentine border and central areas of necrosis.
    The diagnosis should be confi rmed by MRI with and without contrast. The lesion consists
    of highly malignant astrocyte tumor cells that surround areas of necrosis; this is known as
    pseudopalisading. GBM has been associated with genetic alterations, including loss of p53
    function, increased activity of the epidermal growth factor receptor gene (EGFR), and loss
    of heterozygosity on chromosome arm 10q.
    GBM has a poor prognosis, with a mean survival of 8–10 months after diagnosis; most patients
    die within 2 years.
    Answer A is incorrect. Densely packed cells with halos of cytoplasm surrounding large
    round nuclei are characteristic of oligodendrogliomas, which are slow-growing tumors originating
    in the cerebral hemispheres. These lesions have a better prognosis than astrocytomas,
    with a mean patient survival of 5–10 years.
    Answer B is incorrect. Perivascular pseudorosettes with tumor cells surrounding vessels are
    characteristic of ependymomas, which are tumors located in the periventricular space or in
    the spinal cord that may obstruct the flow of cerebrospinal fluid.
    Answer D is incorrect. Sharply demarcated areas of tumor cells located at the grey-white
    matter junction are characteristic of secondary metastatic lesions from a primary tumor elsewhere
    in the body, most commonly the breast, lung, thyroid, skin, kidney, and gastrointestinal tract.
    Answer E is incorrect. A whorled pattern of concentrically arranged spindle cells with calcified psammoma bodies is characteristic of meningiomas, which are the second most common
    primary intracranial neoplasm. Meningiomas are benign, slow-growing tumors of the meninges.

    Rate this question:

  • 3. 

    After a 63-y/o man with a progressive, chronic movement disorder dies, the family requests an autopsy. On gross inspection of the patient’s brain, the pathologist notes the presence of a deep brain stimulator electrode. The pathologist then obtains a tissue specimen of the basal ganglia for histologic analysis (see image) that stains positive for α-synuclein. From which disease did the decedent most likely suffer?

    • A.

      Guillain-Barré syndrome

    • B.

      Huntington’s disease

    • C.

      Parkinson’s disease

    • D.

      Pick’s disease

    • E.

      Werdnig-Hoffmann disease

    Correct Answer
    C. Parkinson’s disease
    Explanation
    The correct answer is C. The tissue section shown demonstrates the presence of a Lewy body, which is a cytoplasmic inclusion consisting of aggregated α-synuclein, ubiquitin, tubulin, and neurofi lament proteins. The Lewy body is believed to result from disrupted proteasomal activity, leading to the accumulation of cellular proteins, which results in the disruption of normal cellular processes. Lewy bodies present in the substantia nigra, in the context of a movement disorder (evidenced by this patient’s history and the presence of a deep brain stimulator), are highly suggestive of Parkinson’s disease.

    Answer A is incorrect. Guillain-Barré syndrome is a demyelinating disease of the peripheral
    nervous system. Lewy bodies are not present.
    Answer B is incorrect. Huntington’s disease is an autosomal dominant disease involving atrophy
    of the caudate nucleus. It is a progressive, terminal neurodegenerative disorder characterized
    by chorea and dementia. Lewy bodies are not present.
    Answer D is incorrect. Pick’s disease is a neurodegenerative disease characterized by progressive
    dementia, aphasia, and parkinsonism.
    Pick bodies (intracellular inclusions of aggregated tau protein), not Lewy bodies, are present
    in affected patients.
    Answer E is incorrect. Werdnig-Hoffmann disease (also known as spinal muscular atrophy) is
    an autosomal recessive disease involving progressive degeneration of the anterior spinal
    horns. Lewy bodies are not present.

    Rate this question:

  • 4. 

    A newborn girl is diagnosed as dysmorphic by a pediatrician in the newborn nursery. On physical examination the girl has a broad neck, wide-spaced nipples, and a systolic ejection murmur. An echo-cardiogram is performed and demonstrates coarctation of the aorta. The echocardiography technologist also runs his transducer across the patient’s abdomen and notices a renal abnormality associated with this patient’s syndrome. The most likely observed renal abnormality increases this patient’s risk for developing which disease?

    • A.

      Neuroblastoma

    • B.

      Ovarian cancer

    • C.

      Transitional cell carcinoma

    • D.

      Uterine cancer

    • E.

      Wilms’ tumor

    Correct Answer
    E. Wilms’ tumor
    Explanation
    The correct answer is E. This patient has classic findings associated with Turner’s syndrome, a genetic disorder resulting from a 45,XO complement of chromosomes. Approximately 25%–30% of patients will have associated renal anomalies, including horseshoe kidney, pelvic kidney, or duplicated collecting systems. Patients with horseshoe kidneys are approximately four times more likely to develop Wilms’ tumor when compared to the general population.
    Answer A is incorrect. Although it has been suggested that patients with Turner’s syndrome
    are at increased risk of developing malignancy, they do not have a specifi c increased risk of developing neuroblastoma.
    Answer B is incorrect. Although it has been suggested that patients with Turner’s syndrome
    are at increased risk of developing malignancy, they do not have a specifi c increased risk of developing ovarian cancer. Familial BRCA gene mutations or no history of childbirth each increases
    the risk of ovarian cancer.
    Answer C is incorrect. Although it has been suggested that patients with Turner’s syndrome
    are at increased risk of developing malignancy, they do not have a specifi c increased risk of developing transitional cell carcinoma. Smoking greatly increases the risk of transitional cell carcinoma.
    Answer D is incorrect. Although it has been suggested that patients with Turner’s syndrome
    are at increased risk of developing malignancy, they do not have a specific increased risk of developing uterine cancer. Unopposed estrogen secretion (eg., hormone replacement therapy
    without progesterone) increases the risk of uterine cancer.

    Rate this question:

  • 5. 

    A 65-y/o man presents to the office with complaints regarding his urine. He states that he has recently had bloody urine, but does not have any urinary pain, hesitation, dribbling, or increased frequency. He also says he has lost 4.5 kg over the past 2 months. A biopsy of the patient’s bladder wall is shown in the image. Which of the following risk factors has the strongest association with this patient’s disease?

    • A.

      History of aniline dye exposure

    • B.

      History of cyclophosphamide treatment

    • C.

      History of heavy cigarette smoking

    • D.

      History of pelvic irradiation

    • E.

      History of schistosomiasis infection

    Correct Answer
    C. History of heavy cigarette smoking
    Explanation
    The correct answer is C. This patient has transitional cell carcinoma of the bladder, as evidenced
    by his painless hematuria and absent signs of prostate cancer. Histology confirms the diagnosis with the presence of invasive transitional cells and prominent, atypical nuclei and mitotic spindles. Numerous factors increase the risk of developing transitional cell carcinoma, the most signifi cant of which is an extensive history of cigarette smoking. Cigarette smoking increases a patient’s risk by three- to sevenfold. Treatment of transitional cell carcinoma largely depends on the stage of disease,
    although these tumors have a tendency to recur regardless of disease stage. Low-grade lesions
    may be treated with excision, whereas higher-grade lesions require a combination of excision and chemotherapy.

    Answer A is incorrect. Aniline dye exposure (eg., in a textile mill worker) is a risk factor for the development of transitional cell carcinoma; however, smoking is the most significant risk factor.
    Answer B is incorrect. Cyclophosphamide therapy (eg., in a patient with a history of treated Ewing’s sarcoma) is a risk factor for the development of transitional cell carcinoma; however, smoking is the most signifi cant risk factor.
    Answer D is incorrect. Pelvic irradiation (eg., in a patient treated for prostatic cancer) is a risk factor for the development of transitional cell carcinoma; however, smoking is the most signifi cant risk factor.
    Answer E is incorrect. Schistosomiasis infection (eg, in a patient with travel to an endemic area, including the Middle East) is a risk factor for the development of transitional cell carcinoma;
    however, smoking is the most significant risk factor.

    Rate this question:

  • 6. 

    A 2-year-old girl is brought to the ED because of fevers that have been occurring daily for 3 weeks. Physical examination reveals a 1.2-kg (2.6-lb) weight loss since her last doctor’s visit 1 month earlier. She also has pallor, hepatomegaly, and splenomegaly. She is admitted to the hospital and undergoes bone marrow aspiration; results are shown in the image. Which of the following is the most likely diagnosis?

    • A.

      Acute lymphoblastic leukemia

    • B.

      Ewing’s sarcoma

    • C.

      Hemophagocytic lymphohistiocytosis

    • D.

      Neuroblastoma

    • E.

      Wilms’ tumor

    Correct Answer
    C. Hemophagocytic lymphohistiocytosis
    Explanation
    The correct answer is C. This patient has symptoms consistent with hemophagocytic lymphohistiocytosis (HLH), and bone marrow aspiration (demonstrating macrophages engulfing
    RBCs) confi rms the diagnosis. Familial-type HLH is an autosomal recessive defect in several
    genes, including perforin-related genes; the secondary type is frequently due to infection with
    Epstein-Barr virus. HLH involves the abnormal activation and proliferation of lymphohistiocytes
    leading to hemophagocytosis and the upregulation of proinfl ammatory cytokines. Treatment
    consists of a combination of etoposide, corticosteroids, and methotrexate, although stem cell
    transplant is often required.

    Answer A is incorrect. Acute lymphoblastic leukemia frequently presents with constitutional
    symptoms (fever, weight loss, pallor, hepatosplenomegaly). Bone marrow aspiration would not demonstrate hemophagocytosis.
    Answer B is incorrect. Ewing’s sarcoma frequently presents in the second decade of life with constitutional symptoms (fever, weight loss), bone tenderness, and pathologic fractures.
    Bone marrow aspiration would not demonstrate hemophagocytosis.
    Answer D is incorrect. Neuroblastoma frequently presents with constitutional symptoms
    (fever, weight loss, pallor, hepatosplenomegaly).
    It is the most common malignancy of infancy. A bone marrow aspirate would not demonstrate hemophagocytosis.
    Answer E is incorrect. Wilms’ tumor frequently presents with an asymptomatic flank mass and/or gross hematuria. It is the most common primary renal tumor in children. Bone marrow aspiration would not demonstrate hemophagocytosis.

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  • 7. 

    Following a course of chemotherapy, a 5-y/o male oncology patient develops altered mental status, tachycardia, decreased blood pressure, flushing of the extremities, and decreased urine output. After 48 hours in the pediatric intensive care unit, the patient dies from complications secondary to overwhelming gram-negative sepsis. At autopsy, the pathologist notes the abnormal appearance of the decedent’s kidneys, as shown in the image. What process most likely caused the findings demonstrated in the image?

    • A.

      Acute pyelonephritis

    • B.

      Diffuse cortical necrosis

    • C.

      Obstructive uropathy

    • D.

      Papillary necrosis

    • E.

      Renal infarction

    Correct Answer
    B. Diffuse cortical necrosis
    Explanation
    The correct answer is B. This patient died from complications secondary to septic shock. The patient had evidence of early end-organ failure as demonstrated by his decreased urine output. Patients suffering from septic shock can develop diffuse cortical necrosis (shown in the image) of the kidneys, which is believed to result from a combination of hypoperfusion, microangiopathic thrombosis, and infarction; thromboses may be present in the arterioles, capillaries, and glomeruli. The areas of necrosis are generally confi ned to the cortex and, on gross examination, are sharply demarcated
    from the rest of the kidney. In cases where the underlying sepsis is quickly treated with fluid
    resuscitation and antibiotics, some function of the kidneys may be preserved; otherwise, overwhelming cortical necrosis usually culminates in death.

    Answer A is incorrect. Acute pyelonephritis results from hematogenous or ascending infection
    of the kidneys. On gross pathologic examination the kidney typically demonstrates patchy areas of abscess formation, but not diffuse, sharply demarcated areas of cortical necrosis as seen in the image.
    Answer C is incorrect. Obstructive uropathy results from a blockage distal to the collecting system of the kidneys. On gross pathologic examination the kidney typically demonstrates dilation of the renal pelvis and calyces, but not sharply demarcated areas of cortical necrosis as seen in the image.
    Answer D is incorrect. Papillary necrosis can result from infection, analgesic overuse, sickle cell disease, and a number of other conditions. On gross pathologic examination the kidney typically demonstrates yellow-white areas of necrosis limited to the papillae, but not sharply demarcated areas of cortical necrosis as seen in the image.
    Answer E is incorrect. Renal infarction results from thromboembolic disease involving the renal
    vasculature. On gross pathologic examination the kidney typically demonstrates wedgeshaped
    areas of yellow-white infarction extending from the medulla to the cortex, but not diffuse, sharply demarcated areas of cortical necrosis as seen in the image.

    Rate this question:

  • 8. 

    A 26-year-old woman visits her physician with complaints of vaginal bleeding after sexual intercourse. She started menses at age 14 years and has 32-day cycles. She acknowledges having unprotected sex with multiple partners. Cytologic specimens are taken from the cervix and vagina. On microscopy, cervical cells have large nuclei with open chromatin; several cells have mitotic figures. What would most likely be present in the specimens that account for these findings?

    • A.

      Double-stranded DNA virus

    • B.

      Gram-negative diplococci

    • C.

      Gram-positive cocci

    • D.

      Single-stranded RNA

    • E.

      Squamous cells covered with bacteria

    Correct Answer
    A. Double-stranded DNA virus
    Explanation
    The correct answer is A. The fi ndings on microscopy indicate a malignant transformation of normal cells. Increased nuclear-to-cytoplasm ratio, open chromatin, and mitotic figures indicate that cells are actively dividing. Given the patient’s history of multiple sexual partners and postcoital bleeding, these cells likely indicate the presence of cervical cancer. Cervical cancer is commonly linked to human papillomavirus infection. The virus can be isolated during cytology through various methods. It is a double-stranded DNA virus.

    Answer B is incorrect. Gram-negative diplococci are not associated with cervical cancer.
    However, they can be found in gonorrhea cervicitis.
    Answer C is incorrect. There are no gram positive cocci associated with cervical cancer.
    Answer D is incorrect. There is no singlestranded virus associated with cervical cancer.
    Answer E is incorrect. Squamous cells covered with bacteria can be found in bacterial vaginosis,
    which causes foul-smelling discharge. There is no known association between bacterial vaginosis
    and cervical cancer.

    Rate this question:

  • 9. 

    A 36-year-old woman with a family history of hereditary nonpolyposis colon cancer (HNPCC) presents to her gastroenterologist for her annual examination. Because of a strong family history of colon cancer, she undergoes yearly colonoscopy. However, she has shown no signs and symptoms of HNPCC and has no significant past medical history. Other than colorectal carcinoma, what is another condition for which she is at increased risk given a family history of HNPCC?

    • A.

      Carcinoma of the endometrium

    • B.

      Cholelithiasis causing cholecystitis

    • C.

      Melanin spots of the buccal mucosa

    • D.

      Pseudopolyps of the small or large bowel

    • E.

      Vitamin B12 defi ciency due to malabsorption

    Correct Answer
    A. Carcinoma of the endometrium
    Explanation
    The correct answer is A. HNPCC, also known as Lynch’s syndrome, is a rare autosomal dominant
    disorder associated with an increased incidence of colorectal cancer. Generally, the syndrome
    is associated with mismatch repair. Approximately 70% of people with the syndrome will develop colorectal cancer, typically at 40–45 years of age. Also, there is a high risk of extracolonic cancer, including endometrial, ovarian, urinary tract, small intestinal, stomach, and biliary cancer. As a result, high-risk patients begin annual screening colonoscopies at age 20–25 years, or 10 years before the age of the youngest diagnosed family member. Women >35 years old typically undergo annual
    endometrial biopsy due to the high risk of endometrial carcinoma.

    Answer B is incorrect. Cholecystitis is secondary to gallstones in 90% of cases. Increased gallstone formation related to HNPCC may be plausible if the patient had undergone resection of the ileum for extracolonic cancer of the small bowel. Gallstones are known to occur in such patients after ileal resection due to disturbed bilirubin metabolism. Moreover, although HNPCC can be associated with biliary cancer, the patient in this case has yet to show signs of HNPCC, and biliary cancer does not
    cause cholelithiasis. Thus, the patient presumably has no increased risk of gallstones or cholecystitis.
    Answer C is incorrect. Melanin spots of the buccal mucosa and lips can be seen in Peutz-Jeghers syndrome. This syndrome involves multiple polyps of the small bowel, although the large bowel and rectum can be involved. The polyps are generally considered to be nonmalignant hamartomas, but cancer can occasionally develop. Peutz-Jeghers syndrome is not associated with HNPCC.
    Answer D is incorrect. Pseudopolyps, also known as infl ammatory polyps, are areas of regenerating,
    normal mucosa around which the mucosa has been lost. This typically occurs in the setting of inflammatory bowel disease but may be seen in colitis related to amebic and schistosomal infection or bowel ischemia. Although these “polyps” are not premalignant, they resemble adenomatous polyps on gross examination and should thus be removed and examined histologically. Pseudopolyps are not associated with HNPCC and are unlikely in this patient with no signifi cant past medical history.
    Answer E is incorrect. Although vitamin B12 defi ciency is most commonly associated with
    pernicious anemia, abdominal surgery secondary to cancer might lead to vitamin B12 deficiency. For example, if the patient underwent gastrectomy for gastric cancer caused by HNPCC, intrinsic factor would not be produced. Furthermore, if the patient underwent bowel resection, including the ileum for small bowel cancer related to HNPCC, B12 could not be absorbed because absorption occurs in
    the ileum. However, the patient in this case has yet to show signs of HNPCC and presumably
    has normal vitamin B12 levels.

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  • 10. 

    A 35-year-old woman presents with dull, persistent flank and abdominal pain, polyuria, nocturia, and frequent urinary tract infections. Physical examination is notable for blood pressure of 150/90 mm Hg and multiple bilateral abdominal masses. Urinalysis is notable for microscopic hematuria and 1+ protein. CT of the abdomen reveals multiple cysts in the kidneys. The patient notes that she was adopted and knows nothing about her family medical history. What is the most likely etiology of this patient’s illness?

    • A.

      A mutation on chromosome 3

    • B.

      A mutation on chromosome 6

    • C.

      A mutation on chromosome 9

    • D.

      A mutation on chromosome 16

    Correct Answer
    D. A mutation on chromosome 16
    Explanation
    The correct answer is D. The patient’s symptoms are consistent with adult polycystic kidney
    disease (APKD), a disease most commonly caused by mutation of the polycystin 1 gene located
    on chromosome 16. APKD can also be caused by a mutation in polycystin 2 located on chromosome 4, although this is less common. APKD is characterized by the growth of renal cysts, which are believed to lead to renal failure by compressing adjacent normal parenchyma.
    The disease often presents in the third or fourth decade of life, and symptoms and signs include abdominal discomfort, frequent urinary tract infections, hematuria, polyuria, and nocturia. Cystic kidneys are often seen on imaging. Mild proteinuria is common. Hepatic cysts, as seen in the image, are also common. The disease is also associated with berry aneurysms and mitral valve prolapse.

    Answer A is incorrect. A mutation on chromosome 3 is associated with von Hippel-Lindau disease, which can not only cause renal cysts but also retinal angiomas and central nervous system hemangioblastomas.
    Answer B is incorrect. A mutation on chromosome 6 is associated with recessive polycystic
    kidney disease, which is associated with a much younger age of onset.
    Answer C is incorrect. A mutation on chromosome 9 is associated with tuberous sclerosis,
    which can not only cause renal cysts, but also presents with adenoma sebaceum and central
    nervous system hamartomas.

    Rate this question:

  • 11. 

    A 3-year-old developmentally delayed girl presents to the pediatric neurologist for evaluation of new onset seizures. The parents are also concerned because the child frequently exhibits inappropriate outbursts of laughter. Physical examination is signifi cant for abnormal facies marked by microcephaly, deep-set eyes, and a large mouth with a protruding tongue. The child’s gait is unstable. The most likely diagnosis is an example of which of the following genetic phenomena?

    • A.

      Anticipation

    • B.

      Heteroplasmy

    • C.

      Imprinting

    • D.

      Locus heterozygosity

    • E.

      Mosaicism

    Correct Answer
    C. Imprinting
    Explanation
    The correct answer is C. This child most likely has Angelman’s syndrome. Individuals with this phenotype have a characteristic facies with microcephaly, maxillary hypoplasia, deepset eyes, and a large mouth with tongue protrusion. Their gait is jerky and “puppet-like,” and their behavior is marked by frequent paroxysms of inappropriate laughter. Severe mental retardation and speech impairment are usually present, and 80%–90% of patients have epilepsy.
    Angelman’s syndrome, along with Prader-Willi syndrome, is a classic example of imprinting, which occurs when the phenotype differs depending on whether the mutation is of paternal or maternal origin. Deletions in Prader-Willi syndrome, a phenotypically distinct disorder, occur exclusively on the paternal chromosome 15, whereas deletions at the same site of chromosome 15 on the maternal
    chromosome result in Angelman’s syndrome.
    Answer A is incorrect. Anticipation is the phenomenon in which the severity of a disease worsens in succeeding generations. This occurs, for example, in triplet repeat diseases such as Huntington’s disease, wherein the triplet repeat tends to lengthen, age of onset decreases, and disease severity increases with successive generations. This does not occur in Angelman’s syndrome.
    Answr B is incorrect. Heteroplasmy describes the presence of both normal and mutated mitochondrial
    DNA. This phenomenon is responsible for the variable expression of mitochondrial inherited diseases.
    Answer D is incorrect. Locus heterozygosity describes the phenomenon by which mutations at different loci can result in the same phenotype. An example of this is albinism, which can be caused by a number of different mutations.
    Answer E is incorrect. Mosaicism occurs when cells in the body have different genetic makeup. This sometimes occurs, for example, in Turner’s syndrome. This does not occur in Angelman’s syndrome.

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  • 12. 

    A mother brings her 5-year-old son to his pediatrician’s office. The boy has been experiencing frequent falls as well as progressive difficulty with walking, jumping, and hopping. Laboratory testing reveals a creatine kinase level of 2840 U/L. Muscle biopsy reveals variation in fi ber diameter, an increased number of internalized nuclei, and muscle fiber degeneration and regeneration. Western blot analysis will most likely reveal the complete absence of which of the following?

    • A.

      Cystic fi brosis transmembrane conductance regulator

    • B.

      Dystrophin

    • C.

      Phenylalanine hydroxylase

    • D.

      Spectrin

    • E.

      Type II collagen

    Correct Answer
    B. Dystrophin
    Explanation
    The correct answer is B. Duchenne’s muscular dystrophy (DMD) is the most common form of muscular dystrophy, affecting 1 in 3500 live male births. Symptoms become evident by the age of 5 years and include delayed walking, clumsiness, weakness in the pelvic girdle muscles, and enlargement of the calf muscles (termed pseudohypertrophy). Laboratory testing reveals an elevated creatine kinase level. DMD is caused by an abnormality of Xp21, the region that codes for dystrophin, a myocyte anchoring protein.
    Answer A is incorrect. Cystic fi brosis transmembrane conductance regulator (CFTR) transports chloride ions across epithelial cell membranes. Mutations of the CFTR gene lead to cystic fibrosis, which is associated with symptoms such as diffi culty breathing, frequent pneumonias, and pancreatic insufficiency.
    Answer C is incorrect. Phenylalanine hydroxylase (PAH) is an enzyme that catalyzes the conversion
    of phenylalanine to tyrosine. Deficiency of PAH leads to phenylketonuria, characterized by problems with brain development, mental retardation, and seizures.
    Answer D is incorrect. Spectrin is a cytoskeletal protein important in maintaining RBC plasma membrane structure. Absence of spectrin leads to hereditary spherocytosis, whose symptoms include anemia, splenomegaly, and jaundice.
    Answer E is incorrect. Type II collagen is the building block of articular and hyaline cartilages.
    Defi ciency of type II collagen leads to a severe form of osteogenesis imperfecta that is usually lethal in the perinatal period.

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  • 13. 

    A 55-year-old recent immigrant from Taiwan presents to the clinic with a 3-month history of worsening nasal congestion, epistaxis, and recurrent ear infections. Physical examination reveals painless fi rm lymph node enlargement in the neck. CT of the head reveal a large mass situated in the upper nasopharynx. Biopsy of the lesion shows large epithelioid cells intermixed with numerous infi ltrating lymphocytes. The infectious agent directly associated with this patient’s pathology is best described by which category?

    • A.

      DNA virus

    • B.

      Eubacterium

    • C.

      Fungus

    • D.

      Mycobacterium

    • E.

      RNA virus

    Correct Answer
    A. DNA virus
    Explanation
    The correct answer is A. This patient has developed nasopharyngeal carcinoma, a condition common in certain parts of the world, including Asia and Africa. Development of this tumor is always associated with infection by Epstein-Barr virus (EBV), a DNA virus in the herpesvirus family. Development of this tumor is believed to be related to a synergistic interaction between EBV and a diet high in carcinogenic nitrosamines (common in foods that has been smoked or preserved). Common symptoms include nasal congestion, epistaxis, ear infections (due to tumor-induced blockage of the Eustachian tubes), and headache.
    Answer B is incorrect. Many bacteria are capable of infecting the nasopharynx; however, none are directly associated with malignancy.
    Answer C is incorrect. Nasopharyngeal zygomycosis is a condition that could present with these symptoms in an immunocompromised patient. However, biopsy would show filamentous nonseptate hyphae and a granulomatous response.
    Answer D is incorrect. Although a tuberculoma in the nasopharynx can be confused with a nasopharyngeal tumor, biopsy would show caseating granulomas with multinucleated giant cells.
    Answer E is incorrect. Although a retrovirus such as HIV can create an immunocompromised
    state favoring the development of a malignancy, it is not the direct cause of tumor formation. Lymphomas can be associated with the retrovirus human T-cell lymphoma virus; however, biopsy would show sheets of malignant T lymphocytes typical of this lymphoma. Other RNA viruses are not associated with malignancy.

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  • 14. 

    A 65-year-old male immigrant from Africa presents to the emergency department after an episode of gross hematuria. He states that he has seen small amounts of blood in his urine from time to time over the past several months. His physical examination is remarkable only for mild hepatosplenomegaly. A urology consult is called, and the urologist performs a bedside cystoscopy. A large fungating mass is seen adherent to the superior part of the bladder. Results of a biopsy are shown in the image. What is the most likely environmental exposure associated with this disease in the patient?

    • A.

      Cigarette smoking

    • B.

      Exposure to aniline dyes

    • C.

      Helminth infection

    • D.

      Infection with a papovavirus

    • E.

      Long-term indwelling catheter

    Correct Answer
    C. Helminth infection
    Explanation
    The correct answer is C. This patient is suffering from squamous cell carcinoma of the bladder.
    Although this condition is rare in the United States, it is the most common type of bladder cancer in the world. The most common cause is chronic irritation by the eggs of the helminth Schistosoma haematobium, which lodge in the bladder wall. Squamous cell carcinoma can be distinguished from transitional cell carcinoma pathologically by its appearance. This specimen shows keratin pearl formation, a common fi nding in squamous cell cancers.
    Answer A is incorrect. Cigarette smoking is the most common risk factor associated with transitional cell bladder carcinoma. In this case, however, the patient’s presentation and pathology are more suggestive of squamous cell carcinoma.
    Answer B is incorrect. Aniline dyes are associated with transitional cell carcinoma, the most common type of bladder cancer in the United States. They are not associated with squamous cell carcinoma of the bladder.
    Answer D is incorrect. Papovaviridae such as human papilloma virus are responsible for genital
    warts and cervical carcinoma. They are not associated with bladder cancers.
    Answer E is incorrect. Long-term catheterization is associated with the development of squamous cell carcinoma of the bladder. Based on the patient’s history, however, there is no reason to assume this patient has had an indwelling catheter at any time.

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  • 15. 

    A patient with AIDS and a CD4+ cell count <50/mm3 is suffering from an infection that affects his lungs, eyes, gastrointestinal tract, and central nervous system. Results of a biopsy are shown in the image. With what is the patient most likely infected?

    • A.

      Candida albicans

    • B.

      Cryptococcus neoformans

    • C.

      Cytomegalovirus

    • D.

      Herpes simplex virus

    • E.

      Mycobacterium avium

    • F.

      Pneumocystis jiroveci

    Correct Answer
    C. Cytomegalovirus
    Explanation
    The correct answer is C. The image shows the typical large, round intranuclear inclusion with perinuclear halo seen in cells affected by cytomegalovirus (CMV) infection. This Cowdry type A bodies are typically referred to as “owl’s eyes” due to their microscopic appearance. In immunocompromised patients, CMV infection can present as retinitis, pneumonitis, infl ammation along the gastrointestinal tract, polyradiculopathy, transverse myelitis, and focal encephalitis. In patients with HIV/AIDS, these sequelae occur most prominently when the CD4+ cell count is 10,000 copies/mm3. CMV can cause further immunosuppression, leading to other opportunistic infections such as Pneumocystis and Aspergillus pneumonia.
    Answer A is incorrect. Candida is a fungus that produces a wide spectrum of diseases, ranging from superfi cial mucocutaneous disease in immunocompetent hosts to invasive illnesses in immunocompromised hosts. Histology reveals round or ovoid yeast cells, hyphae, or pseudohyphae.
    Answer B is incorrect. Cryptococcus neoformans causes meningitis and meningoencephalitis in patients with AIDS. This fungus is difficult to observe with routine hematoxylin and eosin stains, so methenamine silver or periodic acid-Schiff stains are used to identify the characteristic narrow-based buds and round-to-oval yeast, surrounded by a polysaccharide capsule.
    Answer D is incorrect. Herpes simplex virus in HIV-infected individuals can cause recurrent orolabial, genital, and perianal lesions. A Tzanck smear is positive for multinucleated epithelial giant cells. It does not cause the large intranuclear inclusion body shown.
    Answer E is incorrect. Mycobacterium avium causes lung disease in immunocompromised hosts and is subsequently spread via the blood to the liver, spleen, bone marrow, and other sites. Histology of mycobacterium is not consistent with this image. Rather, acid-fast staining would show organisms in foamy macrophages, granulomas, giant cells, and cells with eosinophilic necrosis.
    Answer F is incorrect. Pneumocystis jiroveci (formerly carinii) causes pneumonia in immunocompromised individuals

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  • 16. 

    A 66-year-old woman has an autosomal recessive disease with multiple sequelae, including diabetes mellitus and arthritis. Physical examination reveals hepatomegaly and skin hyperpigmentation. A biopsy of her liver is shown in the image. What is the most likely explanation for her health problems?

    • A.

      Chronic ingestion of alcohol

    • B.

      Genetic defi ciency in the synthesis of β-globin chains

    • C.

      Inappropriately high iron absorption

    • D.

      Mutation in RBC membrane protein

    Correct Answer
    C. Inappropriately high iron absorption
    Explanation
    The correct answer is C. Hereditary hemochromatosis is an autosomal recessive adult onset disorder characterized by inappropriately high iron absorption that leads to progressive iron overload. The organs damaged by iron deposition include the liver, heart, pancreas, pituitary, joints, and skin. Cirrhosis results from progressive iron deposition in the liver parenchyma of patients with hemochromatosis. In the image, hepatocellular iron deposition is seen as granular brown cytoplasmic pigment. Microscopic evidence of cirrhosis includes an increased quantity of connective tissue extending from the portal areas. Cirrhosis, which simply means fi brosis, is the result of past or
    chronic tissue destruction. Acute destruction would be evidenced by the presence of inflammatory
    cells in the portal areas, as is seen in hepatitis.

    Answer A is incorrect. Alcoholic liver disease occurs in patients who are heavy drinkers. Liver biopsy in these patients may show cirrhosis. However, in contrast to patients with hemochromatosis, the hepatic iron levels are relatively normal, and iron stores are usually

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  • 17. 

    A 37-year-old HIV-positive man presents for evaluation of anogenital lesions. He states that the lesions have been present for years, but have recently grown in size and become pruritic and tender. On examination he is circumcised and has multiple hyperkeratotic papules on his penis shaft, perineum, and anal area. He also has a palpable rectal mass with guaiacpositive stool and conjunctival pallor. On further questioning, he admits to recent unintentional weight loss, constipation, and bloating. His CD4+ cell count is 150/mm3 and his hematocrit is 26%. CT scan of the abdomen shows a 3 × 4-cm rectal mass with multiplemetastatic lesions in his liver. What tumor-suppressor protein is targeted by the virus causing this patient’s rectal cancer?

    • A.

      APC

    • B.

      BRCA1

    • C.

      MSH2

    • D.

      NF1

    • E.

      P53

    Correct Answer
    E. P53
    Explanation
    The correct answer is E. This HIV-positive patient has multiple anogenital warts, or condylomata
    acuminata, which are commonly caused by human papilloma virus (HPV) types 6 and 11. A feared complication of condylomata acuminata is anorectal cancer, as seen here. Immunodefi ciency predisposes to the development of HPV-induced transformation. The mechanism of HPV-induced transformation involves the production of a viral protein, E6, which binds to a cellular ubiquitin ligase E6AP. On binding to E6, E6AP polyubiquitinates the tumor suppressor p53, leading to dysregulated cell proliferation and, eventually, oncogenesis.

    Answer A is incorrect. APC is a tumor suppressor gene mutated in certain hereditary forms of colon cancer. The APC protein normally degrades the transcription factor β-catenin, which is involved in colonic epithelial cell proliferation. In the absence of APC, increased levels of β-catenin accumulate, eventually leading to oncogenesis.
    Answer B is incorrect. BRCA1 is a tumor suppressor gene commonly mutated in hereditary forms of breast and ovarian cancers. The BRCA1 protein functions in DNA repair processes, and inherited mutations in BRCA1 interfere with DNA repair, leading to the accumulation of mutations and, eventually, oncogenesis.
    Answer C is incorrect. The MSH2 gene regulates a mismatch repair enzyme and is mutated in certain hereditary forms of colon cancer. In the absence of MSH2, increased levels of DNA
    mutations accumulate, leading to eventual cellular transformation.

    Answer D is incorrect. NF1 is a tumor suppressor gene mutated in neurofi bromatosis type 1. The NF1 protein functions as a GTPase activating protein for the small G protein Ras. Because Ras is only active when it is GTPbound, NF1-mediated GTP hydrolysis leads to inactivation of Ras. In the absence of NF1, Ras is hyperactive, leading to enhanced growth factor signal transduction and, eventually, oncogenesis.

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  • 18. 

    A 5-year-old boy presents with an unsteady gait and severe vertigo and nausea. A brain lesion is seen on CT scan; a biopsy of the lesion is shown in the image. Where in the brain is the patient's lesion?

    • A.

      Cerebellar vermis

    • B.

      Intermediate section of the cerebellar hemisphere

    • C.

      Lateral section of the cerebellar hemisphere

    • D.

      Occipital cortex

    • E.

      Postcentral gyrus of the parietal lobe

    Correct Answer
    A. Cerebellar vermis
    Explanation
    The correct answer is A. The boy’s brain biopsy demonstrates medulloblastoma. This is a poorly differentiated neuroectodermal tumor that occurs predominantly in children and exclusively in the cerebellum. The cerebellar vermis is the medial section of the cerebellum and is responsible for proximal muscle coordination, balance, and vestibulo-ocular refl exes. As seen in this patient, lesions of the vermis lead to vertigo, nausea, and diffi culties in coordinating movement of trunk and proximal limb muscles. The presence of medulloblastoma commonly leads to obstruction of the outflow of cerebrospinal fluid and the potential for hydrocephalus, a life-threatening condition.

    Answer B is incorrect. Medulloblastomas arise in the midline of the cerebellum in children. The intermediate section of the cerebellar hemisphere is more lateral than the vermis. Lesions in the intermediate section would cause deficits in coordinating movements of the ipsilateral distal extremities, not the vertigo and proximal limb problems seen in this patient.

    Answer C is incorrect. Medulloblastomas arise in the midline of the cerebellum in children. Lesions of the lateral hemisphere would likely cause defi cits in planning movements of the ipsilateral distal extremities, not the vertigo and proximal limb problems seen in this patient.

    Answer D is incorrect. Medulloblastomas arise in the midline of the cerebellum in children, not in the occipital cortex. Occipital cortex lesions could lead to defects in vision, not the vertigo and proximal limb problems seen in this patient.

    Answer E is incorrect. Medulloblastomas arise in the midline of the cerebellum in children, not in the parietal cortex. The postcentral gyrus of the parietal lobe is the primary somatosensory cortex. Lesions of this area would cause sensory defi cits, not the vertigo and proximal limb problems seen in this patient.

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  • 19. 

    A 64-year-old retired shipyard worker has been experiencing shortness of breath, a cough, and chest pain for 5 months. In that time he has lost 14.5 kg (32 lb). He develops progressive ascites, and ultimately dies due to a pulmonary embolus. Autopsy results are shown in the image. Exposure to which substance is a risk factor for this patient’s disorder?

    • A.

      Afl atoxin B

    • B.

      Asbestos

    • C.

      Benzene

    • D.

      Cadmium

    • E.

      Silica

    Correct Answer
    B. Asbestos
    Explanation
    The correct answer is B. This image demonstrates an advanced case of mesothelioma, in which the entire left lung is encased with tumor. The clinical history supports this diagnosis. Asbestos is present in certain building materials and fi re-resistant materials, and exposure to asbestos is a risk factor for the development of mesothelioma.

    Answer A is incorrect. Afl atoxin B is produced by Aspergillus and is a common contaminant of cereals, spices, and nuts. It has been associated with carcinoma of the liver.

    Answer C is incorrect. Long-term exposure to high levels of benzene can lead to leukemia and Hodgkin’s lymphoma. Benzene is the main component of light oil, and is found in gasoline and other fuels.

    Answer D is incorrect. Cadmium is a carcinogen associated with the development of prostate
    cancer. It can be found in batteries and in metal coatings.

    Answer E is incorrect. Exposure to silica may occur in the manufacturing of several materials,
    such as glass, ceramics, and electronics. Silicosis is characterized by bilateral, fi ne nodularity in
    the upper lung lobes. It is slowly progressive. Its role as a carcinogen is controversial.

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  • 20. 

    A 59-year-old man is hospitalized after suffering a severe myocardial infarction. He is initially treated with nitrates, β-blockers, and aspirin, and subsequently undergoes cardiac catheterization with placement of two stents. Following the procedure he is hemodynamically stable without recurrence of chest pain. However, 5 days after admission his heart rate is 134/min, blood pressure is 72/35 mm Hg, and respiratory rate is 29/min. Physical examination reveals distant heart sounds and an elevated jugular venous pressure. Which of the following complications is most likely causing this patient’s symptoms?

    • A.

      Aneurysm formation

    • B.

      Cardiac arrhythmia

    • C.

      Fibrinous pericarditis

    • D.

      Rupture of the papillary muscle

    • E.

      Rupture of the ventricular free wall

    Correct Answer
    E. Rupture of the ventricular free wall
    Explanation
    The correct answer is E. This patient is in shock due to cardiac tamponade secondary to the rupture of the ventricular free wall, which usually occurs 4–10 days after the initial myocardial infarction (MI). It usually presents with sudden shock with signs of cardiac tamponade, such as the hypotension, distant heart sounds, and elevated jugular venous pressure observed in this patient. Survival depends primarily on the rapid recognition of myocardial rupture and the provision of immediate therapy, such as urgent pericardiocentesis or surgery. Unfortunately, this complication of an MI is often a fatal one.
    Answer A is incorrect. Aneurysm formation may occur post-MI due to a lack of contractility that results in the infarcted area. Sequelae of ventricular aneurysm formation include decreased cardiac output, increased risk of arrhythmias, and potential mural thrombus formation with risk of mbolization.
    Answer B is incorrect. Cardiac arrhythmias are a common cause of death in the first few days after an MI. However, this patient’s clinical picture is more consistent with a diagnosis of cardiac tamponade secondary to ventricular free wall rupture.

    Answer C is incorrect. Fibrinous pericarditis is a complication that usually occurs 3–5 days post-MI. This condition usually presents with chest pain that is relieved when the patient leans forward; often a pericardial friction rub can be auscultated on cardiac examination. However, this patient’s clinical picture is more consistent with a diagnosis of cardiac tamponade secondary to ventricular free wall rupture.
    Answer D is incorrect. Papillary muscle rupture is another complication of MI that usually occurs 4–10 days post-MI. However, patients with papillary muscle rupture usually present with acute mitral regurgitation, causing the abrupt onset of heart failure in the setting of a new systolic murmur. Emergent surgical intervention is the treatment of choice for this condition.

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  • Mar 22, 2023
    Quiz Edited by
    ProProfs Editorial Team
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    Quiz Created by
    Chachelly
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