Preoperative diagnosis of Lhermitte-Duclos disease by magnetic resonance imaging. Case report.

Lhermitte-Duclos disease is a benign, presumably hamartomatous lesion of the cerebellum which presents clinically as a mass lesion. Pathologically, it consists of thickening of both the molecular and granular cell layers of the cerebral cortex which enlarges the folia but allows for preservation of the gyral pattern of the cerebellar cortex. Preoperative diagnosis with computerized tomography and other studies has not been possible, and even at surgery the diagnosis may be missed because of the preservation of the gyral pattern. The sensitivity of magnetic resonance imaging allows recognition of the cortical nature of the mass lesion, and especially the gyral pattern within the mass lesion, providing a diagnostic image which is unlikely to be confused with any other pathological process in the cerebellum. Preoperative diagnosis of Lhermitte-Duclos disease allows surgeons to plan an appropriate decompressive procedure.