Immunohistochemical demonstration of prostatic origin of metastases

An immunoperoxidase technique for prostate specific acid phosphatase was performed on 14 lymph node metastases of prostatic carcinoma and 13 cases of metastatic adenocarcinoma from other primary sites. Eleven metastatic prostate carcinomas showed diffuse strongly positive immunostain and one showed focal weak positivity. Two prostatic and all other metastatic carcinomas were negative. Thus, the method is found to be extremely specific (100 per cent) and to show a high degree of sensitivity (86 per cent) for the demonstration of the prostatic origin of lymph node metastases.