Adrenal Myelolipoma

Adrenal myelolipoma is a benign tumor of the adrenal gland.  The tumor is often discovered on imaging studies like CT and MRI done for other reasons.  The tumor is benign but can cause symptoms when it grows large, bleeds and pushes on structures next to it.

What is an adrenal myelolipoma?

A benign tumor of the adrenal gland composed of fat and myeloid tissue.  Myeloid tissue is derived from the bone marrow.

Symptoms of adrenal myelolipoma

Many of the tumors are asymptomatic.  The larger tumors can cause abdominal pain, nausea, and vomiting.   Larger tumors can bleed and cause shock.

How is adrenal myelolipoma diagnosed?

Adrenal myelolipomas are diagnosed most commonly on imaging studies like CT and MRI.  Ultrasound can show a mass of the adrenal gland although it is not used for primary diagnosis.  We can not see these tumors on X-rays.

What does adrenal myelolipoma look like on imaging?

-Adrenal myelolipoma on CT

CT is the preferred method of diagnosis.  CT will often show at least some fat within the tumor.  There will also be interspersed soft tissue which represents the myeloid elements.  CT will also be good at showing bleeding from the tumor.

-Adrenal myelolipoma on MRI

MRI will also demonstrate a tumor composed of fat and soft tissue elements.  The tumor will enhance following contrast administration.

What else can look like adrenal myelolipoma in radiology?

Other fat containing adrenal lesions like carcinoma, adrenal adenoma and adrenal lipoma can mimic this tumor.

Tumors containing fat originating from the upper part of the kidney like angiomylolipoma can mimic adrenal myelolipoma.

A retroperitoneal liposarcoma can mimic an adrenal myelolipoma but does not originate from the adrenal gland.

How rare is adrenal myelolipoma?

They are rare occurring in less than .2% of the population.

Is adrenal myelolipoma cancerous?

No.  They are not cancerous and have no known malignant potential.  Fat however can be found in more aggressive growths of the adrenal gland like adrenocortical carcinoma.

Adrenal myelolipoma treatment

Management is often dependent on the size of the mass, confidence in imaging diagnosis and symptoms.  Smaller masses indicative of adrenal myelolipoma can be followed with serial imaging studies.  Large symptomatic lesions or those which have bled can be resected.  This is usually curative.

What type of doctor treats adrenal myelolipoma?

The tumor is often found incidentally or on scans done for other reasons.  A primary care doctor or specialist like an endocrinologist may be involved in the care.  These tumors are associated with other endocrine disorders in some cases.  A surgeon will be involved if resection is deemed necessary.

Adrenal myelolipoma: summary

Adrenal myelolipomas are benign tumors composed of fat and myeloid elements.  They are most commonly found on imaging studies like CT and MRI done for other reasons.

Adrenal myelolipomas can be confidently diagnosed on imaging studies although other fat containing tumors of the adrenal gland and surrounding tissues are in the differential diagnosis.

Smaller tumors are often asymptomatic and not treated.  Larger tumors can be symptomatic or cause bleeds.  They can also be indeterminate for more aggressive tumors which can contain fat.  Treatment may therefore involve surgical resection.