title: Choroid Plexus Papillomas of the Cerebellopontine Angle.
abstract: OBJECTIVE
  Choroid plexus papillomas (CPPs) of the cerebellopontine angle (CPA) are extremely rare. We present a series of 21 cases operated on in the last 7 years at our institution.
  
  
  METHODS
  During the period from January 2008 to October 2015, we encountered 102 histologically established cases of CPPs, of which 21 were located in the CPA region. Clinical profiles, radiologic features, surgical procedures, intraoperative findings, and outcomes were extracted from the patient records and neuroimaging data.
  
  
  RESULTS
  The 21 CPPs in the CPA region accounted for 20.5% of all CPPs. Two of the tumors occurred in pediatric patients. Tumor size was 2.5-4.7 cm. The rate of calcification was higher in the CPPs in the CPA region. Peritumoral cysts and cysts with small nodules were observed in our cases. A far lateral suboccipital approach was chosen for CPPs protruding inferiorly into the foramen magnum region (n = 14), and a suboccipital retrosigmoid approach was chosen for the other tumors. Total resection was achieved in 18 patients, and subtotal resection was achieved in 3 patients. During the follow-up period, only 1 patient experienced recurrence 32 months after the first operation. The recurrence turned out to be an atypical CPP.
  
  
  CONCLUSIONS
  CPPs in the CPA region cannot be easily differentiated from other tumors preoperatively. Cysts and calcifications appear on neuroimaging. CPPs in the CPA region usually protrude inferiorly into the foramen magnum region. As much tumor should be removed as possible to avoid recurrence and malignant transition.
authors: Department of Neurosurgery, Capital Institute of Pediatrics, Chaoyang District, Beijing, China.
authors: Wei
authors: W
authors: Luo
authors: Department of Neurosurgery, China National Clinical Research Center for Neurological Diseases, Beijing Tiantan Hospital, Capital Medical University, Dongcheng District, Beijing, China. Electronic address: ttyycsy@126.com.
authors: Hai
authors: H
authors: Liu
authors: Department of Neurosurgery, China National Clinical Research Center for Neurological Diseases, Beijing Tiantan Hospital, Capital Medical University, Dongcheng District, Beijing, China.
authors: Jiaxin
authors: J
authors: Li
authors: Department of Neurosurgery, China National Clinical Research Center for Neurological Diseases, Beijing Tiantan Hospital, Capital Medical University, Dongcheng District, Beijing, China.
authors: Jun
authors: J
authors: Yang
authors: Department of Neurosurgery, China National Clinical Research Center for Neurological Diseases, Beijing Tiantan Hospital, Capital Medical University, Dongcheng District, Beijing, China.
authors: Yulun
authors: Y
authors: Xu
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002528:Cerebellar Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D002530:Cerebellopontine Angle / Q000000981:diagnostic imaging / Q000601:surgery*; D002648:Child; D005260:Female; D005539:Foramen Magnum; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000379:methods*; D020288:Papilloma, Choroid Plexus / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D012189:Retrospective Studies; D047368:Tumor Burden; D055815:Young Adult
keywords: Cerebellopontine angle; Choroid plexus papillomas; Clinical features; Malignant transition; Surgery