前立腺癌に対するホルモン療法中に異所性ACTH症候群を発症した1例

Abstract

A 74-year old man presented to us with difficulty urinating. The laboratory examinations revealed an elevated prostate-specific antigen (PSA) level. A prostate biopsy revealed prostate adenocarcinoma. The computed tomography scan showed metastasis to lymph nodes in the pelvic cavity and both adrenal glands. Combined androgen blockade therapy was started, and PSA levels began to decrease gradually. However, 2 months later, he was hospitalized for treatment of cellulitis and was found to have hypertension, hyperglycemia, and hypokalemia. Endocrinological studies showed elevated serum adrenocorticotropic hormone (ACTH) and serum and urinary cortisol levels. The plasma cortisol level was not reduced by either the 1 mg or 8 mg dexamethasone suppression test, and the plasma cortisol and ACTHlevels did not respond to the corticotropin-releasing hormone test. Computed tomography indicated increased metastasis, and endocrinological studies and other examinations suggested a diagnosis of ectopic ACTHsyndrome. Combined androgen blockade therapy was continued, and inhibitors of adrenocortical synthesis were also administered. However, 16 weeks later, he died of prostate cancer. On autopsy, the histological examination revealed small cell carcinoma in the prostate and adrenal glands and other sites of metastasis, while immunohistochemistry findings revealed that the tumors in the prostate and adrenal glands were strongly positive for ACTH.