Cerebellum, Dysplastic cerebellar gangliocytoma

Dysplastic cerebellar gangliocytoma (Lhermitte-Duclos disease) is a rare entity associated with Cowden syndrome (mutations in PTEN tumour suppressor gene). Whether it is a hamartoma or a true neoplasm is still debated. The radiologic appearance of widened cerebellar folia is very characteristic (see Related Content). Microscopically, there is diffuse enlargement and architectural distortion of the molecular and granular cell layers of the cerebellum which are filled by dysplastic ganglionic cells. A layer of myelinated fibres can sometimes be seen in the outer aspect of the molecular layer, giving an “inside-out” appearance to the cerebellar cortex. In this case, this is well-demonstrated by the Luxol fast blue stain for myelin. While dysplastic cerebellar gangliocytoma is usually sufficiently treated with surgical resection, patients should be screened for systemic malignancies and other features of Cowden syndrome.