Cerebellar MR in Fukuyama congenital muscular dystrophy: polymicrogyria with cystic lesions.

PURPOSE To determine the MR appearance of cerebellar abnormalities in Fukuyama congenital muscular dystrophy. METHODS We reviewed brain MR images of 25 patients with Fukuyama congenital muscular dystrophy and examined the autopsy specimens of a 23-month-old girl with the disease to determine the pathologic nature of the MR findings. RESULTS MR studies revealed two characteristic cerebellar abnormalities: (a) disorganized cerebellar folia (16 cases) that were recognized as unusual distortions of the cortex; and (b) clusters of intraparenchymal cysts (23 cases). The two lesions were located close to each other, and milder lesions tended to affect only the superior semilunar lobule. The autopsy specimen revealed small cerebellar cysts, which consisted of dilated subarachnoid spaces buried beneath the malformed cortex. CONCLUSION The disorganized folia represent cerebellar polymicrogyria, and the presence of cerebellar cysts is related to the polymicrogyria. These two MR changes are often present in Fukuyama congenital muscular dystrophy and are distinct enough to suggest the radiologic diagnosis.