A 15-year-old girl is brought to the physician because she has had progressive difficulty speaking during the past 6
months. She becomes dizzy and falls frequently. She complains of headache and facial and neck pain. During the past
month, she has had decreasing bladder and bowel control. On physical examination, there is loss of pain and temperature
sensation over the nape of the neck, shoulders, and upper ARMS, but vibration and position sensation are preserved. She
has muscle wasting in the lower neck and shoulders. MRI of the spinal cord shows cervical and thoracic enlargement with
a CSF collection dilating the central canal. MRI of the brain shows gross findings similar to those shown in the figure.
Which of the following is the most likely diagnosis?
A. Arnold-Chiari II malformation B. Cerebral palsy C. Dandy-Walker malformation D. Holoprosencephaly E. Multiple sclerosis F. Polymicrogyria
Arnold-chiari ii malformation-(a) this patient has an arnold-chiari ii malformation, which results in a small posterior fossa, misshapen midline
cerebellum with downward displacement of the vermis, and tenting of the tectal plate. mri in this case is characteristic of
hydromyelia. cerebral palsy is a general term describing nonprogressive motor deficits that are present from birth. dandy-
walker malformation includes hypoplasia or absence of the cerebellar vermis and cystic enlargement of the posterior
fossa. holoprosencephaly is a severe malformation with total (alobar) or incomplete (semilobar) separation of the cerebral
hemispheres in brain development. multiple sclerosis results in white matter plaques of demyelination, not malformation.
polymicrogyria is characterized by numerous, small, irregularly formed gyral contours.
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