Large Bilateral Adrenal Myelolipoma in a Patient with Congenital Adrenal Hyperplasia

Adrenal myelolipoma is a benign and biochemically non-functioning tumor, containing adrenal, adipose, and myeloid tissue. There are some reports of its association with endocrine disorders such as Congenital Adrenal Hyperplasia and Cushing's disease. They are usually smaller than 7 cm but rarely they can grow into giant size and cause compressive symptoms. Here, we present a case with development of giant myelolipoma in a patient with history of congenital adrenal hyperplasia.

Case Description:

46-year-old Caucasian male with past medical history of Congenital adrenal hyperplasia (CAH), carcinoid tumor of duodenum, type 2 Diabetes Mellitus, hypothyroidism, hypertension and obesity was referred by his primary care physician for management of Congenital adrenal hyperplasia. His sister was also diagnosed with CAH. After being referred, his prednisone was changed to hydrocortisone and fludrocortisone was also added. His 17-hydroxyprogesterone and androstenedione levels were highly elevated. Dexamethasone was added at bedtime. Due to persistent elevation of 17-hydroxyprogesterone and androstenedione, his regimen was changed to prednisone with reverse dosing. His ACTH was surprisingly normal, and testosterone was low. His CT Adrenal glands showed bilateral adrenal enlargement: 11 x 10 cm right adrenal mass and 14 x 25 cm left adrenal mass. Patient was referred to Endocrine surgery for elective removal due to compressive symptoms with distension of abdomen and displacement of spleen, pancreas and kidney by left adrenal mass. He underwent open left adrenalectomy which was complicated by massive blood loss, intraoperatively requiring multiple blood and platelet transfusion, so plan for right adrenalectomy was aborted. Bleeding was controlled and the patient made a good recovery within the next several days. Pathology confirmed diagnosis of giant myelolipoma consisting of a very large, markedly distorted adrenal gland that weighed 2835 g and measured 33 x 20 x 9 cm.

Discussion:

Although 10-15% of incidental adrenal adenoma can be myelolipoma, they are small, unilateral, and asymptomatic. In the context of CAH and Cushing’s disease, it has been postulated that prolonged stimulation of the adrenal cortex by high ACTH levels might induce transformation of adrenal tissue into myeloid tissue, contributing to the development of myelolipoma.

Patients with CAH may be at higher risk of developing adrenal myelolipomas. They are mostly discovered in patients who were untreated or were poorly controlled and had chronic ACTH elevation. In contrast, the patient described in this report had been treated for CAH since childhood and had low ACTH but had elevated levels of 17-hydroxyprogesterone and androstenedione, which was difficult to control despite treatment with different steroid regimens. This case suggests adrenal myelolipomas diagnosed in the setting of CAH may not always be associated with elevated ACTH level and they can grow very large causing compressive symptoms.