To report a rare case of recurrent intraventricular hemorrhage (RIVH) revealing atypical choroid plexus papilloma of the lateral ventricle in an adult.

Recurrent intraventricular hemorrhage (RIVH) in adults without a clear vascular cause is rare and poses a diagnostic challenge. Choroid plexus papillomas (CPPs) are uncommon, highly vascular tumors localized in the ventricles and most commonly seen in the pediatric population. These lesions typically present with hydrocephalus, while hemorrhagic onset is exceptionally uncommon. 

A 50-year-old man with a history of hypertension, type 2 diabetes, and chronic alcohol use presented with acute encephalopathy, nausea, vomiting, and headache. Neurological exam showed confusion (NIHSS score: 3), without focal deficits. Blood pressure was moderately elevated.

Initial non-contrast head CT revealed a large IVH in the left lateral ventricle extending into the right lateral and third ventricles, with associated obstructive hydrocephalus but no intraparenchymal bleeding. Head CT angio showed an enlarged choroidal vein within the left lateral ventricle, with no presence of aneurysms or other vascular abnormalities. Brain MRI showed an unrelated small cavernous malformation in the surface of the left frontal lobe, distal to the left lateral ventricle. Two cerebral angiograms similar findings from head CTA with no presence of abnormal shunting lesions.  Following a third IVH episode, endoscopic exploration revealed a vascular lesion with a cauliflower-like appearance. Surgical resection was performed, and histopathology confirmed a choroid plexus papilloma.

This case represents the first description of RIVH as the initial manifestation of atypical CPP in the lateral ventricle of an adult. Unlike typical adult presentations, which usually involve hydrocephalus and fourth ventricular location, this case highlights the need to consider neoplastic etiologies in unexplained, recurrent intraventricular hemorrhage and the potential need to include intraventricular endoscopic exploration in the workup of RIVH.