Extra-adrenal myelolipoma presenting in the spleen: A report of two cases

Abstract

Myelolipoma is a rare neoplasm composed of mature fat and bone marrow occurring most frequently in the adrenal gland with rare occurrences in extra adrenal locations including lung, liver, retroperitoneum, mediastinum and testes. Splenic myelolipomas are seen most commonly in non-human species including cat and dog. Only rare cases of splenic myelolipoma in humans have been reported previously. We present two cases of myelolipoma in the spleen. The first is a 62year old female presenting with abdominal pain and a splenic mass. The second is a 44year old male presenting with hematuria and a mass in the spleen. Both cases showed trilineage bone marrow elements with mature fat. These cases demonstrate that myelolipoma do rarely occur in human spleen and we highlight the distinction from extramedullary hematopoiesis, mature extramedullary myeloid tumor (myeloid sarcoma), lipoma and well differentiated liposarcoma.