Imaging Pearls ❯ Adrenal ❯ Adrenal Myelolipoma
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- “Lipomatous and myelolipomatous degeneration occurs in primary adrenal tumors such as adenoma and rarely ACC. It is much less common than adrenal myelolipomas, which have a reported prevalence of up to 6%. At imaging, these areas of degeneration manifest as foci of macroscopic fat within an adrenal lesion, but they comprise a small percentage of the nodule (mean, 14% of the tumor in one series).”
Adrenal Neoplasms: Lessons from Adrenal Multidisciplinary Tumor Boards
Ryan Chung et al.
RadioGraphics 2023; 43(7):e220191 July 2023
- When do we operate on an Adrenal Myelolipoma?
- Size (usually over 8cm)
- Patient has pain and discomfort
- Atypical CT appearance (not certain it is a AML) - “Laparoscopic adrenalectomy may be appropriate for patients with a presumptive diagnosis of AM and abdominal or flank pain, large tumor size, and/or uncertain diagnosis after imaging.”
Adrenal Myelolipoma: Operative Indications and Outcomes Victoria M. Gershuni et al. J Laparoendosc Adv Surg Tech A. 2014 Jan 1; 24(1): 8–12. - “ According to Olsson et al., the incidence of myelolipoma at autopsy ranges from 0.08% to 0.4%. Males and females are affected equally, and the peak age range at diagnosis is between 50 and 70 years of age.Although most AMs are small and asymptomatic, larger tumors may present with symptoms ranging from nonspecific abdominal pain to spontaneous retroperitoneal hemorrhage.”
Adrenal Myelolipoma: Operative Indications and Outcomes Victoria M. Gershuni et al. J Laparoendosc Adv Surg Tech A. 2014 Jan 1; 24(1): 8–12. - “ A potentially interesting observation in our AM patients is the incidence of obesity. Mean BMI was 36 kg/m2, and most patients were obese; 6 of 13 patients for whom BMI data were available had BMI values >39 kg/m2. These BMI values were also significantly higher than for the rest of our adrenalectomy population. Because fat is a major component of AM, this raises the question of whether AM may be seen more commonly in the era of the obesity epidemic.”
Adrenal Myelolipoma: Operative Indications and Outcomes Victoria M. Gershuni et al. J Laparoendosc Adv Surg Tech A. 2014 Jan 1; 24(1): 8–12. - “Management of adrenal myelolipoma should be considered on an individual basis. Although it is a benign tumor, surgery plays an important role for symptomatic cases and those lesions that cannot be distinguished reliably from malignancy.”
Adrenal myelolipoma: To operate or not? A case report and review of the literature Mary Ramirez1 and Subhasis Misra⁎ Int J Surg Case Rep. 2014; 5(8): 494–496. - “Although traditionally treated conservatively, some studies suggest surgical intervention for symptomatic tumors, growing tumors, or tumors larger than 6 cm in order to reduce the risk of developing abdominal pain or life threatening rupture and hemorrhage.”
Adrenal myelolipoma: To operate or not? A case report and review of the literature Mary Ramirez1 and Subhasis Misra⁎ Int J Surg Case Rep. 2014; 5(8): 494–496.
- “Adrenal myelolipoma is a benign tumor of varied composition of adipose tissue and myelopoietic cells, usually trilinear elements. Myelolipoma is relatively uncommon, occurring in 0.08%–0.2% of cases in autopsy series. These tumors are not hormonally active and usually are asymptomatic, unless they grow to a large size and exert mass effect or have internal hemorrhage. Very rarely, myelolipomatous foci are associated with adrenal functional disorders such as Cushing syndrome.”
From the Radiologic Pathology Archives: Adrenal Tumors and Tumor-like Conditions in the Adult: Radiologic-Pathologic Correlation Grant E. Lattin, Jr et al. RadioGraphics 2014 34:3, 805-829
- Myelolipoma
- Benign
- Nonfunctioning
- Hematopoeitic tissue & mature adipose
- 2-17 cm - Myelolipoma
1. Change over time
- remain stable
- enlarge
- get smaller
2. Complications
- mass effect
- hemorrhage
- “The CT features are characteristic. Lesions usually have a negative Hounsfield unit value owing to macroscopic fat. Because of intermixed hematopoietic tissue, the attenuation is usually higher than that of retroperitoneal fat. High-attenuation regions may be seen due to hemorrhage or calcifications.”
CT and MR Imaging of Extrahepatic Fatty Masses of the Abdomen and Pelvis: Techniques, Diagnosis, Differential Diagnosis, and Pitfalls
Pereira JM et al.
RadioGraphics January 2005 vol. 25 no. 1 69-85 - “Myelolipoma is an uncommon benign tumor composed of mature adipose cells and hematopoietic tissue. The prevalence in autopsy series is between 0.08% and 0.2% . Typically, myelolipoma arises in the adrenal gland. Extra-adrenal myelolipoma is rare and is found most commonly in the presacral and other retroperitoneal areas . Usually asymptomatic and discovered incidentally at cross-sectional imaging, myelolipoma occasionally causes discomfort due to compression or hemorrhage.”
CT and MR Imaging of Extrahepatic Fatty Masses of the Abdomen and Pelvis: Techniques, Diagnosis, Differential Diagnosis, and Pitfalls
Pereira JM et al.
RadioGraphics January 2005 vol. 25 no. 1 69-85 - Myelolipoma
Change over time
-remain stable
-enlarge
-get smaller
Complications
-mass effect
-hemorrhage - Myelolipoma
-Benign
-Nonfunctioning
-Hematopoeitic tissue & mature adipose
-2-17 cm - Adrenal Lesions that Contain Fat: Differential Diagnosis
- Adrenal Myelolipoma
- Adrenal Adenoma
- Adrenal Pheochromocytoma
- Adrenal Carcinoma