When an Adrenal Mass Isn’t Cancer: A Rare Case of <i>Mycobacterium genavense</i> 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 <i>Mycobacterium</i> 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 <i>Mycobacterium</i> infection. The differential diagnosis of an adrenal mass is discussed, and the role of endocrinologists in diagnosing and managing this case is highlighted.