A Rare Case of an Extra-Adrenal Myelolipoma Arising in the Renal Sinus: A Case Report and Review of the Literature

Adrenal myelolipoma is a benign lesion composed of mature adipose tissue and myeloid elements that are generally asymptomatic and detected incidentally, either radiographically or at autopsy. It is a rare entity with an incidence on autopsy series of 0.08–0.2%[1]. Extra-adrenal myelolipomas are well described in the literature and usually found retroperitoneally in the presacral space[2]. They can also occur, however, in a variety of other locations including the stomach, mediastinum, spine, and liver[3,4,5,6,7,8,9,10,11,12,13]. A total of 16 cases of perirenal myelolipoma have been reported in the literature to date[2,14,15,16,17,18,19,20,21,22,23,24]. Of these, only one originated in the renal sinus[23]. We report only the second case, to our knowledge, of an extra-adrenal myelolipoma originating from the renal sinus and review the literature on this rare tumor.