Large Bilateral Adrenal Myelolipomas in the Setting of Congenital Adrenal Hyperplasia

Abstract

Adrenal myelolipomas (AMLs) are rare benign adrenal tumors containing adipose and hematopoietic tissue, with a reported incidence of 0.08 to 0.4% on autopsy. AMLs are the second most common primary adrenal incidentaloma. Congenital adrenal hyperplasia (CAH) is associated with 10% of analyzed AML cases, half of which are bilateral in CAH patients.This is a 40-year old male with CAH diagnosed shortly after birth, due to 21-hydroxylase deficiency. He was doing well on a maintenance dose of hydrocortisone 20mg PO qAM and 10mg PO qPM and fludrocortisone 0.2mg PO daily until two years ago when he was incidentally found to have large bilateral AMLs while undergoing abdominal MRI and CT scans. These measured 6.6x3.6x7.7cm on the right (R) and 12.3x8.4x6.8cm on the left (L) at the time. He was asymptomatic, denying flank and abdominal pain. Follow up adrenal CT a year later revealed his AMLs increased in size to 8.7x4.2x6.6cm (R) and 13.9x6x8cm (L). Repeat CT another year later showed further rapid enlargement of his AMLs, measuring 11.1x6.1x7.9cm (R) and 17.1x7.8x10.8cm (L). He also exhibited a rising 17-hydroxyprogesterone level of 11,547ng/dL, despite an increased hydrocortisone dose (20mg BID). Although he remained asymptomatic, due to the precipitous growth of the masses and his increasing steroid requirement, a surgical approach was recommended. Open bilateral adrenalectomy was performed by an experienced endocrine surgeon and patient was discharged from the hospital with maintenance hydrocortisone and fludrocortisone therapy as well as strict sick day instructions.AMLs were first described in 1905 by Gierke. In the past, they were often discovered on autopsies, but more recently, due to the increase in imaging, have been incidentally diagnosed on more patients. Mostly, they occur unilaterally and are small (<4 cm) in size. Individuals with hormonal dysfunction such as those with Cushing’s Syndrome, Conn’s syndrome and CAH, particularly with difficult-to-control corticotropin levels, may be at a greater risk of developing AMLs concurrently, however this phenomenon is still not well understood. Small asymptomatic AMLs can be monitored with serial imaging over time. Spontaneous rupture of AMLs was found in 4.5% of cases, mostly occurring in tumors > 10cm, some resulting in retroperitoneal hemorrhage or even hemorrhagic shock. Although there is no clear consensus on surgery, development of symptoms or significant growth (to >10cm), as in our case, is a reason to pursue surgical evaluation especially in a young, otherwise relatively healthy adult.