Block 7 Skin Creighton Univ W Xpl Prt 1

Melanocytes are found in the stratum basale, the deepest layer of the epidermis, at the dermoepidermal junction.

Ehlers-Danlos syndrome is an autosomal dominant disorder involving the gene for peptidyl
lysine hydroxylase.

Junctional epidermolysis bullosa refers to a group of autosomal recessive disorders caused
by a mutation in the gene for laminin 5.

The correct answer is "stratum basale and papillary dermis". Bullous pemphigoid is an autoimmune disorder that targets the basement membrane between the epidermis and the dermis. In this condition, IgG antibodies are deposited between the stratum basale (the deepest layer of the epidermis) and the papillary dermis (the upper layer of the dermis). This deposition leads to the formation of blisters and bullae in the affected area.

Dendrocytes are found in the dermis

The delayed type IV hypersensitivity reaction begins when Langerhans cells are exposed to an antigen (such as poison ivy). The antigen is then presented to CD4+ T cells. These T cells are responsible for producing the eczema upon re-exposure. They produce cytokines which attract inflammatory cells such as neutrophils.

Tetracyclines are bound to calcium in newly formed teeth both in utero and in young children. They may cause discoloration and enamel dysplasia

This is bullous pemphigoid, a disease caused by IgG antibodies against the basement membrane between the epidermis and dermis. In the picture, the epidermis and dermis have separated. In pemphigus vulgaris, the antibodies are directed against desmosomes within the epidermis. In either case, immunosuppression by steroids is the most effective treatment.

Like question 33, the real tipoff is knowing that cellular pattern on the biopsy. Fibrosarcoma looks like a herrigbone patten. This tumor commonly presents as a slow growing painless mass in the upper extremity. Here's what the biopsy would look like. Below it is what a herringbone pattern looks like

This is an example of palasading cells. They form a ring around the tumor islands. This is evident in cancers resulting from the basal cell layer in the epidermis.

The storiform patten of spindle cells is most characteristic of dermatofibrosarcoma. The other lesions tend to involve keratinocytes. Another reasonable answer for this biopsy would be Kaposi sarcoma, especially if we knew that the patient was immunosuppressed.

Rhabdomyosarcoma (malignant skeletal muscle tumor) is a small blue cell tumor and is the most common soft tissue sarcoma in children. It comes in three types, perhaps the most important is embryonal. It may present as a grape-like mass protruding from the vagina. Knowing this rather distinct presentation should be easy points on a test.

Stevens-Johnson syndrome is a more extensive form of erythema multiform that involves both the skin and the mucosal membranes. Both are type II hypersensitivity reactions.

This is seborrheic keratosis. It is a common, benign lesion which exhibits epidermal hyperplasia and horn cysts

He most likely has many seborrhei keratoses. These can develop as an explosion of growth, which is associated with paraneoplastic syndrome. This is called the Leser-Trelat sign. His age and smoking history put him at high risk for lung cancer

These are typical findings for the CD8+ T cell mediated injury to myofibers in dermatomyositis. If there were no rash, polymyositis would be likely. Additional tests to diagnose include EMG of the muscles, and biopsy.

The real tipoff here is that the biopsy has a pinwheel patten. Dr. Hunter describes it as 'storiform'. Malignant fibrous hisiocytoma is the most common sarcoma of the elderly
(60s & 70s). Not only is it common, but it's deadly since it metastasizes up to 50% of the time.

Piebaldism is an autosomal dominant disorder and is basically a localized albinism.

Don't use a potent steroid on warm, wet areas such as the face, axilla, and groin. Potent steroids tend to be fluorinated. Since the lesion is 'wet' (weeping), it would be better to use a lotion. Lotions, powders, and wet dressing are better for acute inflammation which tends to be wet. Chronic inflammation should be treated with an ointment. For example, an area of severe scaling lichenification would be treated with a fluorinated ointment.

Dermatomyositis is a complement mediated, small vessel vasculitic myopathy that results in perifascicular atrophy. Dr. Brumback made a point to repeat that statement. Polymyositis differs grossly in that it does not involve a rash and microscopically in that lymphocytes invade the muscle fibers. Both polymyositis and dermatomyositis result in proximal muscle weakness (ie trouble getting out of a chair) and elevated plasma muscle enzymes (CKP, myoglobin). Kearns-Sayre syndome is one of many mitochondrial myopathies. This presents as eye muscle paralysis. Leber's optic atrophy results in blindness.