Fourth ventricular solitary fibrous tumor: a case report and review of the literature

INTRODUCTION Solitary fibrous tumors of the central nervous system usually present as dura-based masses and clinically resemble meningiomas. There are very few reported cases of intra-ventricular solitary fibrous tumors, particularly in the fourth ventricle. CASE PRESENTATION Our patient was a 52-year-old African-American man, who presented to our facility with a two-month history of progressive weakness and numbness in all extremities. A computed tomography scan and brain magnetic resonance imaging scan revealed a homogeneous, avidly enhancing 4.5 × 3.7 × 2.7cm fourth ventricular mass, with compression of adjacent medulla and cerebellum and extension into the foramen of Luschka. Our patient underwent a suboccipital craniotomy and resection of the tumor. A histological examination showed a spindle cell neoplasm with prominent collagenized stroma. The neoplastic cells were strongly and diffusely positive for CD34, vimentin and Bcl-2, and negative for S-100, CD99 and epithelial membrane antigen. The molecular immunology Borstel-1 (MIB-1) proliferation index was low (1%). CD31 immunostain highlighted the endothelial cells but the spindle cells were negative. Reticulin stain demonstrated a moderate reticulin network but individual cells were not invested by reticulin fibers. The histological features and immunoprofile was consistent with a solitary fibrous tumor. CONCLUSIONS In the central nervous system, solitary fibrous tumors are usually indolent tumors, with only rare examples showing hypercellularity and increased mitotic activity; features that were absent in our patient's case. We present an uncommon central nervous system neoplasm in a rare location. Although uncommon, solitary fibrous tumors should be included in the differential diagnosis of intra-ventricular tumors in adults.