Primary seminal vesicle carcinoma: An immunohistochemical analysis of fourcases

Primary adenocarcinoma of the seminal vesicles is an extremely rare neoplas m. Because prompt diagnosis and treatment are associated with improved long -term survival, accurate recognition of this neoplasm is important, particu larly when evaluating limited biopsy material. Immunohistochemistry can be used to rule out neoplasms that commonly invade the seminal vesicles, such as prostatic adenocarcinoma Previous reports have shown that seminal vesicl e adenocarcinoma (SVCA) is negative for prostate-specific antigen (PSA) and prostate-specific acid phosphatase (PAP); however, little else is known of its immunophenotype. Consequently, we evaluated the utility of cancer anti gen 125 (CA125) and cytokeratin (CK) subsets 7 and 20 for distinguishing SV CA from other neoplasms that enter the differential diagnosis. Four cases of SVCA-three cases of bladder adenocarcinoma and a rare case of adenocarcinoma arising in a mullerian duct cyst--were immunostained for CA -125, CK7, and CK20. Three of four cases of SVCA were CA-125 positive and C K7 positive. All four cases were CK20 negative. All bladder adenocarcinomas and the mullerian duct cyst adenocarcinoma were CK7 positive and negative for CA-125 and CK20. In addition, CA-125 immunostaining was performed in ne oplasms that commonly invade the seminal vesicles, including prostatic aden ocarcinoma (n = 40), bladder transitional cell carcinoma (n = 32), and rect al adenocarcinoma (n = 10), and all were negative for this antigen. In conc lusion, the present study has shown that the CK7-positive, CK20-negative, C A-125-positive, PSA/PAP-negative immunophenotype of papillary SVCA is uniqu e and can be used in conjunction with histomorphology to distinguish it fro m other tumors that enter the differential diagnosis, including prostatic a denocarcinoma (CA-125 negative, PSA/ PAP positive), bladder transitional ce ll carcinoma (CK20 positive, CA-125 negative), rectal adenocarcinoma (CA-12 5 negative, CK7 negative, CK20 positive), bladder adenocarcinoma (CA-125 ne gative), and adenocarcinoma arising in a mullerian duct cyst (CA-125 negati ve).