Choroid Plexus Papilloma (WHO Grade I)
Choroid Plexus Carcinoma (WHO Grade III-IV)
Cell of Origin: Choroid plexus epithelium

Common Locations:
Adults - Fourth ventricle
Children - Lateral ventricle

Demographics: Children > Adults. 40-50% papillomas seen in first year of life, 85% < 5 yrs. May be a congenital. Carcinomas usually seen only in pediatric age group.

Clinical Presentation: Hydrocephalus with headaches

Histology: Papillomas have characteristic lobulated gross appearance. Most are well-differentiated and may resemble normal choroid plexus, however, anaplastic transformation may occur. Parenchymal invasion suggests carcinoma, but can be seen with benign tumors as well.

Transformation of papilloma into carcinoma has been reported.

Special Stains: Cytokeratin distinguishes CPP from ependymoma; Prealbumin (transthyretin) may be helpful (although choroid metastases may also stain positive)
Progression: CSF seeding may occur in both papillomas and carcinomas.

Radiology: Well-demarcated intraventricular (or cerebellopontine angle) mass with hydrocephalus. Calcification especially frequent in fourth ventricular tumors. In adult patients the fourth ventricle is more common. The tumor is attached to the choroid plexus.

Comments: Hydrocephalus may reflect multiple factors, including CSF over-production, ventricular obstruction, and impaired CSF reabsorption. Can present as a congenital brain tumor or neoplasm.

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[REF 1]
"Choroid plexus tumours are rare epithelial brain tumours and limited information is available regarding their biology and the best treatment. A meta-analysis was done to determine prognostic factors and the influence of various treatment modalities. A thorough review of the medical literature (1966-1998) revealed 566 well-documented choroid plexus tumours. These were entered into a database, which was analysed to determine prognostic factors and treatment modalities. Most patients with a supratentorial tumour
were children, while the most common sites in adults were the fourth ventricle and the cerebellar pontine angle. Cerebellar pontine angle tumours were more frequently benign. Histology was the most important prognostic factor, as one, five, and 10-year projected survival rates were 90, 81, and 77% in choroid plexus-papilloma (n=353) compared to only 71, 41, and 35% in choroid plexus-carcinoma respectively (P<0.0005). Surgery was prognostically relevant for both choroid plexus-papilloma (P=0.0005) and choroid plexus-carcinoma (P=0.0001). Radiotherapy was associated with significantly better survival in choroid plexus-carcinomas.

Eight of 22 documented choroid plexus-carcinomas responded to chemotherapy. Relapse after primary treatment was a poor prognostic factor in choroid plexus-carcinoma patients but not in choroid plexus-papilloma patients. Treatment of choroid plexus tumours should start with radical surgical resection. This should be followed by adjuvant treatment in case of choroid plexus-carcinoma, and a "wait and see" approach in choroid plexus-papilloma. Copyright 2002 Cancer Research UK"

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