Disseminated prostatic carcinoma simulating primary lung cancer. Indications for immunodiagnostic studies.

Recognition of disseminated adenocarcinomas potentially responsive to current treatment programs is an important objective in the management of cancer patients. Metastatic adenocarcinoma of the prostate gland is a malignant entity which often can be palliated effectively by hormonally based therapeutic strategies. In cases of metastatic prostate cancer presenting with typical clinical features, the correct diagnosis can be readily achieved, but in patients with less obvious presentations the diagnosis of prostatic carcinoma may be overlooked. In the current report, a group of elderly men presenting with a clinical syndrome resembling either metastatic primary adenocarcinoma of the lung or primary adenocarcinoma of the lung coexisting with prostate cancer were found in fact to have metastatic prostatic carcinoma as their sole disease process. In each case, cytologic characterization of clinically involved tissue specimens by the prostate specific antigen and prostatic acid phosphatase immunohistochemical markers enabled clinical investigators to arrive at the correct diagnosis. Other clinical features, such as a positive bone scan and an enlarged prostate gland on physical exam and/or radiographic studies were noted to be present in these patients. All the patients in the current series responded to hormonal treatment regimens once the diagnosis of metastatic prostate cancer had been established. In elderly male patients presenting with what appears to be primary adenocarcinoma of the lung, the diagnosis of metastatic prostate cancer should be considered and when necessary evaluated by the use of appropriate clinical and immunohistochemical studies.