Monday, May 14, 2012

Posterior Fossa Tumors: Differential Diagnosis #14

The Daily Diff for today is posterior fossa tumors in pediatric patients. Since most intracranial tumors in children occur in the posterior fossa, this is a handy differential to keep in your back pocket. The mnemonic BEAM can help you remember the diagnoses:

DiseaseNotes
BBrainstem glioma
EEpendymomaSpreads around structures "toothpaste tumor"
AAstrocytoma (pilocytic)Most common (85%), usually eccentric with a cystic component
MMedulloblastomaMidline, compresses cerebellum

Conversely, of all the intracranial astrocytomas, 60% of them occur in the posterior fossa. All of these tumors (except brainstem glioma) can have "drop metastases" to the spinal cord, so it is important to image the spine if such a mass is encountered.

Hemorrhagic pilocytic astrocytoma
Source: Radiopaedia

References: