SAT-LB42 Bilateral Large Calcified Adrenal Leiomyoma Mimicking Adrenal Malignancy: A Rare Case Report With Literature Review

Abstract

Background: Adrenal leiomyoma is a very rare benign soft tissue tumor, it is even more unusual if presenting bilaterally; 21 cases have been reported in the literature and only six had bilateral involvement; 5 in the pediatric population and only one in an adult patient. Radiological appearance may frequently be confused with malignancy especially if large, calcified and with central necrosis. We report a rare case of bilateral, large, calcified, non-functioning adrenal leiomyoma in a 20-year-old female, who was suspected for a malignancy preoperatively. Clinical Case: A 20 year-old-female presented with chronic abdominal discomfort, fatigue, and inability to gain weight. On examination, she was normotensive, underweight with BMI of 15.6 kg/m2, and there were no stigmata of Cushing’s syndrome, Addison’s disease or pheochromocytoma. A contrast CT scan of the abdomen revealed the presence of bilateral well-defined suprarenal lesions measuring 8.5 x 8.5 x 7.2 cm and 4.7 x 4.2 x 3.5 cm on the right and left side, respectively. The lesions showed large central areas of necrosis with multiple punctate calcifications and heterogenous peripheral enhancement. The radiological differential diagnosis included adrenal cortical carcinoma, adrenal metastasis, infectious etiology, and bilateral pheochromocytoma. Her hormonal assays showed normal free cortisol and catecholamine metabolites in the urine and normal serum androgens. Thus, the tumors were concluded to be non-functioning. Adrenal insufficiency was ruled out after a short Synacthen test. The patient underwent a successful right adrenalectomy. Resected specimen measured 10 x 9.5 x 7.5 cm. Histology revealed a well-circumscribed and pseudo-encapsulated smooth muscle tumor comprised of bland, spindle-shaped cells. The panel of immunohistochemical stains supported the diagnosis of leiomyoma. Postoperatively, the symptoms improved, she gained 4 kg weight over the following 4 months, and short Synacthen test confirmed an intact adrenal function. To avoid lifelong adrenal insufficiency and after discussion with the patient, we agreed to leave the left adrenal mass and follow it by serial imaging. There was only a minimal increase in the size over the following 4 years (5.5 x 4.5 x 3.8 cm). Conclusion: Adrenal leiomyoma is an extremely rare adrenal tumor and can be confused with adrenal malignancy. Therefore, it should be considered in the differential diagnosis of adrenal incidentalomas. In the case of bilateral etiology, permanent adrenal insufficiency and longterm replacement therapy can be avoided in certain population by removing the larger tumor and continuous follow-up for the other side.