Cushing's syndrome due to an ACTH-producing primary ovarian carcinoma

Although Cushing's syndrome has been described in association with various neuroendocrine tumors producing ectopic adrenocorticotropin (ACTH), primary ovarian carcinoma rarely causes this syndrome. We hereby report the case of a 61-year-old woman presented with abdominal distension, facial swelling and skin pigmentation. Clinical and diagnostic evaluation revealed a right ovarian tumor with hypercortisolemia, high plasma ACTH, extremely high plasma ACTH precursors and lack of dexamethasone suppression. Removal of the tumor led to normalization of ACTH, ACTH precursors and cortisol levels. In addition, hypokalemia, hyperglycemia and elevated serum CA 125 were noted, which were also normalized after resection of the tumor. Histopathological examination indicated a primary ovarian carcinoma with a mixed pattern of differentiation. Immunohistochemistry showed immunoreactivity for chromogranin A, synaptophysin and ACTH. Hence, the diagnosis of Cushing's syndrome arising from an ovarian carcinoma secreting ectopic ACTH was made. The case was managed successfully, with subsequent good recovery and no evidence of recurrence at 4 years of follow-up.