Myelolipomas are benign neoplasms of the adrenal glands that consist of both adipose and hematopoietic tissue which are usually small and have a prevalence of 0.1% in autopsy studies (1). Although adrenal masses occur in 11% of all Congenital Adrenal Hyperplasia(CAH) patients, only 6.5% of these tumours are Myelolipomas (2).
Myelolipomas are usually discovered incidentally, and the malignant potential of an incidental adrenal mass is proportional to its size (3). However several case reports of large Myelolipomas are described in patients with CAH (4).
A 42-year-old man with CAH who had reasonable disease control on long term Prednisone therapy presented to his gastroenterologist with severe colitis. Disease control of colitis was not achieved by either steroidal or non steroidal therapy. An incidental 18cm left adrenal mass was found on MR Enterography with mixed areas of solid and fat density. A malignant adrenal lesion (liposarcoma) could not be ruled out on imaging characteristics alone. There was no evidence of adrenal hormone hyper secretion on biochemical testing and the mass did not increase in size on short duration serial imaging. The mass was resected completely together with the spleen and descending colon due to the strong suspicion of adrenal malignancy. Surgical histology revealed an Adrenal Myelolipoma. He proceeded to have a stormy post operative course
The case highlights that patients with CAH may present with incidental adrenal tumours that are both large and benign such as Myelolipomas. In these patients the size of an adrenal mass lesion alone is a poor predictor of malignant potential. Increased awareness of such cases in CAH patients is required .