Giant myelolipomas and inadvertent bilateral adrenalectomy in classic congenital adrenal hyperplasia

Myelolipomas have been reported in patients with congenital adrenal hyperplasia (CAH). ACTH excess, as seen with non-adherence to glucocorticoid therapy, may be responsible for tumor development. We report a case of a 51-year-old man with classic salt-wasting CAH managed on prednisone 7.5 mg daily and fludrocortisone who presented with chronic back pain and was found to have giant bilateral retroperitoneal masses. On computed tomography (CT) imaging, the masses were heterogeneous, but contained predominantly low-density fat attenuation. The tumors were resected due to concern for malignancy and mass symptoms. Pathologic examination identified both retroperitoneal masses as myelolipomas. The left tumor was 34×20×13 cm and weighed 4.7 kg and the right tumor was 20 cm in the largest dimension. Adrenal tissue was present in the specimen. The patient reported long-term compliance with glucocorticoid treatment. However, no biochemical monitoring of ACTH levels had occurred. Therefore, it is unclear if ACTH excess contributed to the development of these large tumors in this patient. It was presumed that both adrenal glands were inadvertently removed during surgery and the patient was treated with physiologic replacement doses of hydrocortisone and fludrocortisone postoperatively. In this case, the bilateral adrenalectomy was inadvertent. However, adrenalectomy can be considered as a treatment option in patients with classical CAH under certain circumstances to avoid complications of glucocorticoid excess. Learning points Myelolipomas should be considered in the differential diagnosis of adrenal or retroperitoneal masses in patients with CAH. On CT imaging, myelolipomas are seen as heterogeneous masses with low-density mature fat interspersed with more dense myeloid tissue. Myelolipomas are usually unilateral and measure <4 cm; however, very large and bilateral tumors have been reported. Treatment of CAH typically involves using supraphysiologic doses of glucocorticoid to suppress adrenal hyperandrogenism. Bilateral adrenalectomy is an alternative treatment option in patients with CAH. There is an association between ACTH excess and increased incidence of adrenal myelolipoma but the direct causal link remains to be established. Background Myelolipomas are typically benign unilateral adrenal neoplasms measuring <4 cm. The tumors are comprised of adipose and myeloid tissue and are biochemically inert. Their incidence is ∼0.08–0.4% in the general population. They show no gender predilection and typically occur in the fifth to seventh decade of life (1). With the advent of modern imaging techniques, they are most commonly incidental findings (2) but can rarely present with acute abdominal pain due to torsion, infection, or hemorrhage. Computed tomography (CT) is the most sensitive and specific imaging modality for diagnosing myelolipomas. Myelolipomas appear as heterogeneous masses on CT imaging consisting of very low-density adipose tissue (usually <−30 Hounsfield units (HU)) interspersed with myeloid tissue of relatively higher density. Although adrenal adenomas may also appear as low-density lesions, they are typically more dense and homogeneous than myelolipomas (3). An increased frequency of adrenal tumors, particularly myelolipomas, has been reported in patients with congenital adrenal hyperplasia (CAH). One study found a 4% incidence of myelolipoma in patients with CAH (4). Rarely, very large bilateral myelolipomas have been reported in CAH, particularly in the presence of non-adherence to glucocorticoid therapy. It has been postulated that adrenocorticotropic hormone (ACTH) excess stimulates tumor growth (5) (6). Treatment of classic salt-wasting CAH due to 21-hydroxylase deficiency requires lifelong glucocorticoid and mineralocorticoid replacement. Glucocorticoid therapy provides hormone replacement and reduces adrenal androgen production. The importance of androgen suppression in adult men not desiring fertility is unclear. Optimal dosing of glucocorticoids in CAH is challenging, and the consequences of prolonged glucocorticoid excess can be significant, including weight gain, metabolic disturbances, and bone loss. Studies on bilateral adrenalectomy as an alternate treatment option in CAH are limited, and this treatment has typically been restricted to patients who are refractory to medical therapy.