Choroid plexus papillomas: an immunohistochemical study with particular reference to the coexpression of prealbumin

Immunocytochemical characterization of choroid plexus neoplasms was performed in seven cases, five being of benign choroid plexus papilloma (CPP) and the other two of malignant choroid plexus papilloma (choroid plexus carcinoma CPC). Immunohistochemical examination was performed with antibodies to glial fibrillary acidic protein (GFAP), S-100 protein, prealbumin, carcinoembryonic antigen (CEA), epithelial membrane antigen (EMA), and gamma-enolase. All of the five CPPs were positive for GFAP, S-100, prealbumin, and gamma-enolase; and four of them were positive for EMA. None of the CPPs was positive for CEA. Both of the two cases of CPC were positive for gamma-enolase, and one was positive for GFAP, S-100, EMA, and CEA. No CPC showed positivity for prealbumin. This report is the first to describe the usefulness of prealbumin reactivity for histological diagnosis of choroid plexus papillomas.