Primary Leptomeningeal Medulloblastoma: Desmoplastic/Nodular Medulloblastoma without a Discrete Parenchymal Mass

Medulloblastoma is one of the most common pediatric CNS malignancies and the most common primary tumor of the posterior fossa in children. Medulloblastoma can present with leptomeningeal seeding in up to 33% of patients at presentation. Primary leptomeningeal medulloblastoma without a discrete parenchymal mass has been reported 6 times in the literature to date, in both the pediatric and adult populations. This report aims to review the literature of these rare cases and present the first case of a primary leptomeningeal medulloblastoma with a desmoplastic/nodular subtype.