[Clinicopathological study on choroid plexus tumors: immunohistochemical features and argyrophilic nucleolar...

Immunohistochemical features and numbers of argyrophilic nucleolar organizer regions (Ag-NORs) were investigated on 6 cases with choroid plexus tumors: 3 adult and one pediatric cases with choroid plexus papilloma (CPP) and 2 pediatric cases with choroid plexus carcinoma (CPC) clinicopathologically. One of the 2 children with CPC developed a recurrence with dissemination to the CSF and died 2 years postoperatively (case 6), while the other survived following surgery (case 5). This outcome suggested the existence of biological differences in these tumors. We conducted an immunohistochemical examination of prealbumin, S-100 protein, glial fibrillary acidic protein (GFAP), cytokeratin (CKER), and epithelial membrane antigen (EMA) using avidin-biotin complex (ABC) methods and the silver colloid staining technique for Ag-NORs. All 4 CPP were positive for prealbumin and S-100 protein, with 3 of them being strongly positive; 3 of 4 were positive for GFAP and 2 were positive for CKER and EMA. Two cases of CPC were weakly positive for prealbumin. However the part of reserved papillary structure of case 5 was strongly positive for it. The tumor of the survived child was positive for S-100, GFAP, CKER, while negative for EMA. A positivity for S-100 protein and prealbumin was associated with a good outcome, whereas that for GFAP, CKER, and EMA was not. The mean number of Ag-NORs in the 2 cases with CPC exceeded that in cases with CPP. Of the 2 cases with CPC, fetal one (case 6) showed a higher number of Ag-NORs than the survived patient.(ABSTRACT TRUNCATED AT 250 WORDS)