[Lhermitte-Duclos disease. Granulomolecular hypertrophy of the cerebellum]

A case of Lhermitte-Duclos disease is reported. The onset is unusually sudden in a 16 years-old girl. However cerebellar lesions and hydrocephalus are of long duration as showed the skull base anomalies. This slow evolution is the rule in many cases previously reported, which suggests that the disease is due to a dysplasic disorder, perhaps one of cellular differentiation of the cerebellar cortex.