Choroid plexus tumours--an immunohistochemical analysis with review of literature.

Immunohistochemical analysis of 9 choroid plexus papillomas (CPPs) and 3 choroid plexus carcinomas (CPCs) using a panel of antibodies against glial fibrillary acidic protein (GFAP), cytokeratin (CK), epithelial membrane antigen (EMA), S-100 protein, vimentin (vim), and neuron specific enolase (NSE) is presented. Focal positivity was observed for GFAP in 11, vimentin in 7, cytokeratin in 2 and EMA in 3 cases. Diffuse and intense immunoreactivity for S-100 protein was seen in all papillomas, however, unreactive areas were noted in carcinomas. All cases exhibited focal to diffuse NSE positivity. Location and type of the tumour and age of the patient did not influence the staining pattern except for predominant S-100 positivity in papillomas. The significance of these findings is discussed in relation to the differential diagnosis or immunoreactivity patterns of these tumours.