Adrenal Incidentaloma: Challenges in Diagnosing Adrenal Myelolipoma

Adrenal myelolipomas (AMLs) are rare benign adrenal tumors, containing adipose and hematopoietic tissue, a result of reticuloendothelial cell metaplasia. Incidence on autopsy has been reported from 0.08% to 0.4%. AMLs are generally considered nonsecretory. The functional aspect of adrenal incidentaloma should be evaluated. In this article, we report a case of a 40-year-old male, who presented with uncontrolled hypertension and renal failure, with imaging revealing an adrenal incidentaloma. He was started on dialysis for acute fluid overload, and workup for pheochromocytoma revealed an elevated serum norepinephrine level of 1181 pg/mL. Free metanephrine and normetanephrine levels were low when checked pre- and post-dialysis. Complete resection of the encapsulated right adrenal mass was performed. Pathology of the adrenal tumor demonstrates an 11.5 × 9.5 × 7.5 cm well-circumscribed, partially encapsulated proliferation of mature adipose tissue with admixed hemopoietic elements consistent with myelolipoma weighing 29.3 g. This case highlights the inclusion of a full metabolic workup for all adrenal incidentalomas, including AML.