Choroid plexus papilloma (CPP) accounts for <1% of all the intracranial neoplasms and is a rare benign neoplasm with common sites being the fourth ventricle in adults and lateral ventricle in children. They are occasionally bilateral with associated hydrocephalus. A 28-year-old female with no past medical history presented to the emergency department with a fall and witnessed seizure. On her way to the bathroom, she felt dizzy and missed a step leading her to trip and fall hitting her headfirst. While on the floor she was witnessed a seizure and brought to the emergency department where she had postictal confusion, slow speech, and was unable to recall events after falling. She also complained about fatigue, lack of energy, sleepiness, loss of interest, sad mood, and suicidal thoughts. CT scan demonstrated a 2.6 cm fourth ventricular mass with internal calcifications. Posterior to the mass there was a subtle increased density which was favored as additional calcifications with moderate obstruction of the 4th ventricle and mild ventriculomegaly. Differential diagnosis included subependymoma, ependymoma as well as astrocytoma. Histopathological examination revealed CPP with appropriately controlled stains to be positive for S100 and Ki-67 to be approximately 3% and negative for p63. CPP is derived from neuroectoderm and is designated as Grade I neoplasms by WHO and Grade II is reserved for atypical CPP. The most optimal treatment strategy is resection which is curative with very little chance of recurrence after a gross-total resection in approximately 96% of the cases. One of the management challenges faced is the vascularity of the tumor which is due to the intraventricular location of tumor which has a rich anastomotic supply of choroidal blood vessels. Due to the rich vascularity of the tumor embolization is considered as an adjunct to reduce the intravascular blood loss intraoperatively with the overall mortality ranging from 0-25% and the mortality rate from the blood loss to be approximately 12%. Currently, the patient is doing well without any evidence of metastasis. Hence it is important to be aware of this rare and benign entity and endoscopic removal is recommended despite the intraoperative bleeding it might cause.

Citation Format: Hansini Laharwani, Vijay Kumar, James Neill. Choroid plexus papilloma: A report of a benign but rare entity [abstract]. In: Proceedings of the AACR Virtual Conference: Thirteenth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2020 Oct 2-4. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(12 Suppl):Abstract nr PO-235.