Lhermitte-Duclos disease: case report with computerized tomographic scan.

Lhermitte-Duclos disease is a rare, benign cerebellar condition that mimics a posterior fossa mass and has never been diagnosed preoperatively. Grossly, the diseased cerebellar tissue is tough and poorly demarcated; microscopically, the cortex has a thick outer layer of nerve fibers, an inner layer of abnormal ganglion cells, and the absence of normal Purkinje cells. The prognosis, based on cases treated surgically since 1955, is good. A case is reported in which cranial computerized tomography performed 5 years after the partial removal of abnormal tissue showed neither enhancement nor radiolucency.