Rare huge bilateral adrenal myelolipoma confused with retroperitoneal liposarcoma.

Introduction: Adrenal myelolipomas are uncommon benign adrenal tumors, which mostly occur unilaterally. We describe a rare case of giant bilateral adrenal myelolipoma mistaken for retroperitoneal liposarcoma. Case presentation: A 49-year-old man developed fever, left flank pain, and a large mass in his left abdomen. Plain computed tomography showed a 23-cm mass with fat-containing components in the retroperitoneal cavity, suggestive of retroperitoneal liposarcoma. A similar 9-cm mass was observed in the right adrenal gland, suggesting adrenal metastasis. With a clinical diagnosis of retroperitoneal liposarcoma, we administered preoperative radiation therapy and performed a bilateral tumor resection. On postoperative day 9, a surgical site infection occurred, necessitating incisional drainage and the administration of intravenous antibiotics. The histopathological diagnosis was bilateral myelolipoma of the adrenal glands. Conclusion: In cases of bilateral retroperitoneal tumors with a large fat component, adrenal myelolipoma should be considered in the differential diagnosis to avoid overtreatment.