From the Guidelines
Myelolipoma should be managed with repeat imaging in 6-12 months if asymptomatic and without symptoms, as recommended by the Journal of the National Comprehensive Cancer Network 1. When a myelolipoma is identified, it is crucial to assess its size and symptoms to determine the best course of action.
- Key considerations include:
- Tumor size: Myelolipomas can vary in size, and those larger than 4 cm may require closer monitoring or even surgical intervention if they are causing symptoms or show significant growth 1.
- Symptoms: While many myelolipomas are asymptomatic, some may cause pain due to hemorrhage or mass effect, necessitating surgical removal 1.
- Imaging characteristics: Myelolipomas typically appear as well-circumscribed lesions with fat density components on imaging studies, which helps differentiate them from other adrenal masses 1.
- The management approach should prioritize minimizing morbidity and mortality while maintaining quality of life.
- For asymptomatic myelolipomas without aggressive features, periodic imaging follow-up is generally recommended, with the frequency depending on the tumor's size and growth rate 1.
- Surgical intervention, such as laparoscopic adrenalectomy, may be considered for larger tumors, those causing symptoms, or in cases where there is suspicion of malignancy based on imaging features 1.
- It is also important to perform baseline hormonal evaluation in patients with incidentally discovered myelolipomas to rule out functional adrenal tumors, as myelolipomas themselves are non-functional 1.
From the Research
Definition and Characteristics of Myelolipoma
- Myelolipoma is a rare and benign, hormonally inactive tumor that frequently occurs in the adrenal gland 2, 3, 4, 5, 6.
- It is composed of mature adipose tissue with admixed haemopoietic elements 4.
- Myelolipomas are usually asymptomatic and incidentally discovered on cross-sectional imaging 2, 3, 6.
Diagnosis of Myelolipoma
- Radiographic findings can suggest the diagnosis, including a characteristic mass that is lucent on plain films, echogenic on US, shows fat attenuation on CT, is avascular at angiography, and has a signal intensity similar to that of fat on T1-weighted MR images 5.
- Percutaneous needle biopsy is a simple, safe, and effective way to establish the diagnosis when imaging features are not typical 5.
- CT imaging can reveal an encapsulated, sharply delineated mass with an average attenuation of -30 Hounsfield units, which is pathognomonic for myelolipoma 4.
Management and Treatment of Myelolipoma
- Symptomatic tumors, growing tumors, or tumors larger than 10 cm should be excised surgically by means of an endoscopic or conventional approach, depending on the size 2, 4.
- Surgery is indicated in the presence of a tumor diameter above 6 cm, rapid tumor growth, imaging suspicious of malignancy, radiological signs of local invasion, functioning ipsilateral adrenocortical adenoma, pressure-related symptoms, and signs of retroperitoneal bleeding or spontaneous tumor rupture 4.
- Small (<4 cm), homogeneous, non-hormone secreting incidentalomas with an attenuation of <10 Hounsfield units on non-contrast CT are considered benign and require neither treatment nor follow-up 4.
- Adrenalectomy should be considered in symptomatic patients with large tumors and when there is evidence of hemorrhage or tumor growth 3.
Follow-up and Prognosis
- Most myelolipomas are incidentally discovered and can be followed without surgical excision 3, 6.
- A close follow-up should be maintained in the case of patients free of symptoms, and for those with a definite diagnosis from imaging procedures 2.
- The median size change of myelolipomas is 0 mm, and the median growth rate is 0 mm/y, indicating that most myelolipomas do not grow significantly over time 3.