Cushing's syndrome in prostate cancer. An aggressive course of prostatic malignancy

We report a case with an initial diagnosis of adenocarcinoma of the prostate in whom Cushing's syndrome developed. The disease did not respond to estrogen treatment and the patient died of severe septicemia. Histopathologic examination of the autopsy specimens revealed a small cell carcinoma intermingled with a moderately differentiated adenocarcinoma in the prostate and widespread metastases of small cell carcinoma. Immunoreactivity for neuroendocrine differentiation was found only in the small cell carcinoma. Determination of different tumor markers in plasma samples showed markedly elevated levels of prostate-specific antigen as well as carcinoembryonic antigen prior to treatment, with no significant changes after treatment. The concentration of the neuroendocrine marker chromogranin A was initially within the normal range, but increased during estrogen treatment, whilst neuron-specific enolase was moderately elevated throughout the observation period.