Hemihypertrophy, hemimegalencephaly, and polydactyly.

We present clinical and neuropathological details of a patient with hemihypertrophy and hemimegalencephaly who may have Proteus syndrome. The observation of polysyndactyly in the case indicates either that polysyndactyly is a rare manifestation in Proteus syndrome, or that a separate condition, mimicking Proteus syndrome and pursuing a similar clinical course, might exist.