Lhermitte-Duclos disease, or dysplastic cerebellar gangliocytoma, is a rare entity(5-7) associated with the phosphatase and tensin homolog, a tumor suppressor gene, the alteration of which results in replacement of the cerebellar internal granule cell layer(7) with loss of normal structure, leading to thickening and enlargement of the cerebellar folia(6). This evidence concerns the gene PTEN and Lhermitte-Duclos disease.