ANGIOMYOLIPOMA OF THE RENAL SINUS: CASE REPORT AND REVIEW OF THE LITERATURE

Background/Aim: Angiomyolipoma (AML) is a well-known type of tumor; its name is derived from three components: blood vessels, smooth muscle, and fat. It is an uncommon tumor that though benign in most cases can present difficult management decisions. An AML that originates from the renal sinus rather than the renal parenchyma is extremely rare and is therefore difficult to differentiate from other fat containing masses, such as lipomatosis, lipoma, and liposarcoma (1). Only 14 cases of AML involving or originating in the renal sinus have been previously reported in literature (2). We present a rare case of a partially exophytic AML of the renal sinus in a 56 a year-old woman with a relatively rapidly growing. Case Report: A 56-yearold woman visited a hospital in April 2016 for diagnostic evaluation of a right kidney mass renal tumor that had been detected during a routine medical checkup. Neither she nor anyone in her family had a history of tuberous sclerosis (TS). Computed tomography (CT) showed a 4.2×3.4×4.6 cm mass originating from the right renal sinus. The mass was mainly composed of fat with some contrast enhancement, and was subsequently diagnosed as an AML of the renal sinus. In May 2017, she was referred to our department for follow-up of the mass. CT revealed a 6.4×5.1×6.2 cm mass originating from the right renal sinus and that appeared to extend into the perinephric soft tissues (Figure 1). Considering the rapid growth of the first lesion and that the mass was significantly pushing aside the duodenum, though the patient had no symptoms associated with the enlarged tumor, a surgical resection of the mass was performed. Surgery was performed using an intra-operative ultrasonography to identify intrarenal lesions margins and renal masses were removed without need of vascular clamping and renal warm ischemia. The patient was discharged after 4 days without postoperative complications. The definitive histopathological examination confirmed the radiologic diagnosis of renal angiomyolipoma At six months CT scan follow-up, no local or metastatic recurrence was documented, preserving a renal function unchanged. Discussion and Conclusion: AML has an incidence of 0.1-0.22% in the general population, and is four times more frequent in women than in men (1). The lesions may present as sporadic cases or in association with TS. TS is an autosomal dominant neurocutaneous disorder that may affect several organs, e.g. brain, skin, eyes, heart, kidney and lungs.