Giant renal angiomyolipoma presenting as a forme fruste of Wunderlich syndrome: A case report

Renal angiomyolipoma (AML) is the commonest benign renal mesenchymal tumour; giant lesions (>10 cm) carry a high risk of spontaneous haemorrhage. A 45-year-old woman presented with left flank pain and severe anaemia (haemoglobin 4.5 g/dL) without haematuria. Computed tomography showed a fat-containing left renal mass (10.9 × 10.5 × 14.7 cm) with enhancing solid areas, perinephric stranding without discrete haematoma, and additional intrarenal AMLs, consistent with contained intratumoral haemorrhage, a forme fruste of Wunderlich syndrome. Open radical nephrectomy after transfusion was uneventful; histopathology confirmed multifocal triphasic angiomyolipoma. Giant AML should be considered when a fat-containing retroperitoneal mass accompanies unexplained anaemia.