Dysplastic gangliocytoma of the cerebellum (Lhermitte-Duclos disease).

The case of a 30-year-old male patient is presented who was admitted with a 3-month history of elevated intracranial pressure and reduced-hearing on the right. CT revealed hydrocephalus due to displacement of the 4th ventricle by a large non-enhancing cerebellar mass with calcifications. MRI sequences showed a space-occupying lesion within the right cerebellar hemisphere with unusual septations. At operation, the poorly demarcated lesion was excised from the apparently normal surrounding cerebellar tissue and histologically proven to be a dysplastic gangliocytoma (Lhermitte-Duclos disease). Clinical and neuroradiological appearance of this rare entity, as well as hypotheses on its pathogenesis are discussed.