When an Adrenal Mass Isn't Cancer: A Rare Case of Mycobacterium genavense Mimicking a Neuroendocrine Tumor

An adrenal mass is an abnormal growth or tumor that develops in one or both adrenal glands. These can be benign or malignant. They are common, with a prevalence of 1% to 6% in the general adult population. While opportunistic infections such as histoplasmosis and cryptococcosis are known to rarely cause adrenal masses (<1%), with histoplasmosis presenting as an adrenal mass in 0.85% of cases in HIV patients, the incidence of Mycobacterium species causing adrenalitis is even lower, making it an infrequent clinical entity. We present a case of a patient without any obvious immunocompromise who presented with a unilateral adrenal mass initially thought to be a neuroendocrine tumor due to markedly elevated pancreatic polypeptide. He underwent a right adrenalectomy due to the increasing size of the mass and was diagnosed with an adrenal Mycobacterium infection. The differential diagnosis of an adrenal mass is discussed, and the role of endocrinologists in diagnosing and managing this case is highlighted.