SAT-201 Adrenal Myelolipoma in a Patient with Sickle Cell Disease

Background: Adrenal myelolipoma is a rare benign tumor of the adrenal gland, consisting of adipose tissue and hematopoetic elements. It has been reported to be associated with many chronic diseases such as haematological disorders. The majority of the adrenal myelolipomas are diagnosed in the fourth-sixth decades of life, usually as incidental findings. Despite its benign behavior, it may cause difficulties in the differential diagnosis. Clinical Case: A 33-year-old woman was found to have a right adrenal incidentaloma in a kidney ultrasonography, during work-up for suspected kidney pathology ultimately not confirmed. Her past medical history was significant for sickle cell disease. There was no history of hypertension nor personal or family history of endocrine diseases. The physical examination was unremarkable. The ultrasonography revealed a mass above the right kidney, measuring 5.5 cm in diameter, markedly heterogeneous and hypoechoic in the center. On CT imaging, one month later, this mass measured 6.2x4.3cm. The absolute contrast washout of 52% was indeterminate for adrenal adenoma. The MRI, twelve months later, showed a well-demarcated and heterogeneous tumor with 8x4.7x4cm, with fat areas, suggesting adrenal myelolipoma, but not excluding the possibility of a malignant lesion, such as liposarcoma. The mass was in contact with the liver although not invading it nor the kidney or inferior vena cava. There was no evidence of metastatic disease. Basal biochemical work-up did not disclose hormonal hypersecretion. The ACTH level was 19.6 pg/ml (N7.2-63.3); free urinary cortisol (24 hours) was 101 μg/24h (N36-137) and the overnight 1 mg dexamethasone suppression test was also normal (0.5 μg/dL). Serum metanephrines were within the normal range: metanephrine 7,8 pg/mL (N <65) and normetanephrine 52,3 pg/mL (N<196). Her remaining laboratory values were within normal values including potassium and sodium values. Due to the size, rate of growth and atypical features of the mass, right laparoscopic adrenalectomy was performed. The resected adrenal weighed 66.6g and within it there was an intraparenchymal nodule, measuring 7.5 x 3 x 3.5 cm, which on histologic examination proved to be an adrenal myelolipoma. Conclusion: Adrenal myelolipomas are usually clinically silent. However, their incidental diagnosis should warrant careful diagnostic study. Although the pathogenesis of these tumors remains unclear, theories include retention of embryonic rests, adrenocortical metaplasia and extramedullary hematopoiesis. In this patient with sickle cell disease, bone marrow elements within the myelolipoma may have grown as a result of the persistent anemia. Particular to this case is the patient’s young age, since most cases reported have occurred during the fourth-sixth decades of life. In addition, the association with sickle cell anemia has only been reported in a few cases.