What's Under the Tent? Posterior Fossa Tumors in Children, Beyond the Usual Suspects, Part 2

This article is the second in a two-part series on posterior fossa tumors in children. While Part 1 focused on the “usual suspects”—including medulloblastoma, pilocytic astrocytoma, diffuse midline glioma, ependymoma, and atypical teratoid/rhabdoid tumor—Part 2 shifts attention to the differential diagnosis of less common entities. Although individually rare, these atypical tumors collectively account for up to 15% of all posterior fossa neoplasms in children. Part 2 provides a clinical and histological overview of these rare tumors, incorporating relevant epidemiology data, current genetic/molecular classification according to the fifth edition of the World Health Organization Classification of Tumors of the Central Nervous System, and characteristic imaging features. Finally, it briefly addresses pseudoneoplastic conditions that may mimic true neoplasms in the pediatric population.