A Case of Ectopic ACTH Syndrome Associated with Metastatic Prostate Cancer

ABSTRACT

Ectopic adrenocorticotropic hormone (ACTH) syndrome is mostly associated with neuroendocrine tumors and small cell carcinoma of the lung. This syndrome of prostate cancer is rare and has been reported in only a few cases. We report a patient with ectopic ACTH production associated with metastatic prostate cancer. A 70-year-old patient with metastatic prostate cancer was admitted to our hospital with septic shock. He had a history of hormonal therapy and transurethral prostatectomy. Adrenocortical function was checked due to consistent fever and poor general condition, which revealed markedly increased levels of basal plasma ACTH and serum cortisol. The patient did not present typical signs of the Cushing's syndrome, however, hypokalemia and a history of hypertension were found. He died in days as a result of multi-organ failure. On pathology, the prostatectomy specimen showed a tumor composed of mixed populations of adenocarcinoma and small cell carcinoma. The tumor cells in the small cell component were positive for chromogranin and ACTH. Although neuroendocrine differentiation in prostate cancer is rare, etopic ACTH production should be considered in patients with prostate cancer as well as in clinical features of ACTH hypersecretion.