What are the key imaging and clinical features of Dysplastic Cerebellar Gangliocytoma (Lhermitte-Duclos Disease), and its association with Cowden syndrome?

Dysplastic Cerebellar Gangliocytoma, also known as Lhermitte-Duclos Disease, is characterized by a striated cerebellar mass on MRI, appearing hyperintense on T2-weighted images and isointense or hypointense on T1-weighted images. It is considered a hamartoma, and approximately 50% of patients have Cowden syndrome, which includes a spectrum of manifestations such as colonic polyps, cutaneous tumors, and increased risk of breast and thyroid neoplasms. A common pitfall is mistaking it for a cerebellar neoplasm; however, the lack of significant enhancement and the striated pattern are distinguishing features. CT scans may appear normal, making MRI the preferred diagnostic modality.