Cushing syndrome associated with prostatic tumor adrenocorticotropic hormone (ACTH) expression after maximal androgen blockade therapy

We report a patient with adenocarcinoma of the prostate, who eventually developed Cushing syndrome due to ectopic adrenocorticotropic hormone (ACTH) secretion from the tumor. At first, maximal androgen blockade (MAB) therapy was effective for the prostate carcinoma, which was positive for prostate-specific antigen (PSA) and negative for ACTH on the biopsy specimen. However, 3 years later, the patient complained of bilateral leg edema. A chest computed tomographic (CT) scan showed bilateral pleural effusion and inflammatory changes, focused on the right upper-lobe. While his PSA was not elevated, and there were no obvious tumor metastases, his serum cortisol and ACTH levels were elevated, without any evidence of lesions that could release ectopic ACTH. Two weeks later, the patient complained of dyspnea and bilateral pleural effusion, and inflammatory changes were worse. Although the patient was administered inhibitors of adrenocorticoid synthesis-metyrapone, they did not have enough clinical efficiency. Steroid pulse therapy was also administered but the patient's severe pneumonia and pleural effusion did not improve and he finally died of respiratory failure. In contrast to the initial biopsy specimen findings, on autopsy, the tumor was negative for PSA but positive for ACTH. Thus, it would appear that the tumor began to produce and release ectopic ACTH after therapy, which resulted in the development of Cushing syndrome in this patient with prostate carcinoma.