An unusual cause of posterior fossa mass: Lhermitte-Duclos disease.

Lhermitte-Duclos disease (LDD) (dysplastic cerebellar gangliocytoma) is a rare disorder of unknown pathogenesis, presenting with signs and symptoms resulting from obstruction of cerebrospinal fluid flow and mass effect in the posterior fossa. Magnetic resonance imaging is the diagnostic modality of choice allowing preoperative diagnosis with characteristic findings. Surgery is the choice of treatment. The typical histopathological findings of LDD are characterized by widening of the molecular layer, absence of the Purkinje cell layer and hypertrophy in the granule cell layer. Herein we report an adolescent girl with LDD diagnosed preoperatively by the conventional and advanced MR techniques.