Atypical Choroid Plexus Papilloma of the Fourth Ventricle in an Adult: A Case Report.

Atypical choroid plexus papilloma (aCPP) is very rarely seen in adults. Here, we present the case of a 47-year-old male with several months of headache, nausea, dizziness, and imbalance who was found to have an enhancing mass of the fourth ventricle with imaging findings suggestive of likely ependymoma. The patient underwent suboccipital craniotomy with C1 laminectomy and telovelar approach for gross-total resection of the lesion, with final pathology demonstrating WHO grade II aCPP. Subsequent genomic analysis showed a biologically relevant TERT mutation, as well as several variants of unknown significance. We conclude that aCPP is a rare, benign entity diagnosed by tissue sample that is potentially curative with surgical resection and may harbor targetable genetic mutations.