Adrenal Myelolipoma

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Adrenal myelolipoma is a benign (noncancerous) tumor of the adrenal gland, mostly composed of fat and bone marrow elements. Johns Hopkins experts Amir Hamrahian, M.D., medical director of the Comprehensive Adrenal Center, and Lilah Morris-Wiseman, M.D., chief of endocrine surgery, discuss adrenal myelolipoma and what it means if you are diagnosed with one.

What You Need to Know

Adrenal myelolipomas account for about 4% to 7% of all tumors discovered on the adrenal glands.
Adrenal myelolipomas are often found by chance, such as during an ultrasound or CT scan for another medical concern.
Myelolipomas are relatively slow growing, but some can grow very large.
Unless you are experiencing symptoms such as bleeding, pain or pressure, you may not need treatment beyond observation and monitoring.

What causes adrenal myelolipoma?

“The adrenal glands are located just above your kidneys, and they make different hormones,” Hamrahian says. “The causes of adrenal myelolipomas are not well understood, but may be related to a person’s genes (chromosomes) and may be influenced by hormones.” Adrenal myelolipomas may be found in patients with congenital adrenal hyperplasia (a group of rare genetic diseases that lead to an imbalance in hormones made by the adrenal glands).

Other diseases that may be associated with myelolipomas include blood disorders, especially if they are associated with chronic anemia.

What are the symptoms of adrenal myelolipoma?

Morris-Wiseman says a person can have an adrenal myelolipoma and not realize it unless it becomes large enough to cause symptoms. “These tumors are usually found accidentally, when doctors are looking for something else,” she says. “Giant myelolipomas, which can grow larger than 10 centimeters — the size of a softball — are more likely to produce symptoms due to compression of body organs.”

Larger adrenal myelolipomas can cause symptoms such as:

Abdominal discomfort or pain
Pain along the sides of the abdomen and hips (flank pain) or lower back
Abdominal mass
Nausea, with or without vomiting

How is adrenal myelolipoma diagnosed?

“CT scans and MRIs are the preferred imaging tests to diagnose adrenal gland tumors, including myelolipomas,” Hamrahian says. “It is important to differentiate myelolipomas from other adrenal gland tumors.

“So, in addition to imaging studies, your health care provider might want to evaluate your hormone levels,” he explains. “That way, we can ensure the tumor does not make too much of any hormones that the adrenal glands normally make.”

How is adrenal myelolipoma treated?

You may not need any treatment at all, Morris-Wiseman says. “If the diagnosis of myelolipoma is established based on imaging studies like CT or MRI and it isn’t causing any symptoms, you don’t need surgery. Observation and monitoring are sufficient.”

Observation and monitoring may involve getting ultrasound or CT studies regularly so your doctor can check the tumor’s size and rate of growth.

Surgery. Your doctor may want to do more than monitor any large adrenal myelolipoma that is causing pain, nausea or pressure in your abdomen. “Surgical treatment may be necessary if observation reveals that the tumor is growing quickly, or the tumor is producing excessive hormone,” Morris-Wiseman says.

Some experts recommend removing myelolipomas once they get to be 6 or 10 centimeters in size (larger than a baseball or softball). In that case, the doctor may recommend surgery to remove the tumor along with the adrenal gland if necessary.