ACTH-producing adrenocortical carcinoma: an exceedingly rare diagnosis.

Background: Adrenocortical carcinoma is a very rare endocrinopathy that has a poor prognosis and is frequently associated with ACTH-independent Cushing's syndrome. Despite having an adrenocortical carcinoma, our patient surprisingly had an ACTH-dependent Cushing's syndrome.

Case report: A 26-year-old female presented with Cushing's syndrome and an abdominal mass. Imaging studies revealed an adrenal mass consistent with a high-grade malignancy. Laboratory workup showed hypercortisolism, hyperandrogenism, and hypokalemia with normal levels of metanephrines. Unexpectedly, her ACTH levels were remarkably elevated. The pathological analysis of a tumor sample was conclusive for adrenocortical carcinoma with immunopositivity for ACTH.

Conclusions: Our patient suffered from an adrenocortical carcinoma that was ectopically producing ACTH. This case emphasizes that physicians should have a broad-minded approach when evaluating cases of rare endocrine malignancies.