Extraventricular Intraparenchymal Choroid Plexus Tumors in Cerebral Hemisphere: A Series of 6 Cases.

OBJECTIVE Extraventricular intraparenchymal choroid plexus tumors (CPTs) in the cerebral hemisphere are extremely rare. The aim of this study was to investigate the clinical characteristics, radiologic findings, and surgical outcomes of this atypical type of CPT. METHODS The study comprised 6 patients with pathologically proven extraventricular intraparenchymal CPTs who were surgically treated at Qilu Hospital of Shandong University. The PubMed database was searched for similar cases published before January 2015, and these cases were reviewed. RESULTS Patients were 5 (83.3%) men and 1 (16.7%) woman with an average age of 46.5 years. Symptoms and signs of CPT were usually associated with increased intracranial pressure and invasion of functional areas by tumor. Magnetic resonance imaging commonly demonstrated a contrast-enhancing intraparenchymal mass with cysts; hydrocephalus was not observed in any cases. Subtotal resection and gross total resection were achieved in 1 (16.7%) and 5 (83.3%) cases, respectively. There were 3 cases (50.0%) of choroid plexus papilloma, 2 cases (33.3%) of atypical choroid plexus papilloma, and 1 case (16.7%) not otherwise specified. There was a low incidence of postoperative complications, and surgical outcomes of CPTs were satisfactory. CONCLUSIONS In contrast to typical lesions, extraventricular intraparenchymal CPTs in the cerebral hemisphere are rarely associated with hydrocephalus. Magnetic resonance imaging features are key in preoperative diagnosis; nevertheless, it is difficult to distinguish this atypical type of CPT from other lesions. Surgical removal of the tumor is safe and efficacious.