Aneurysm in a Large Sporadic Renal Angiomyolipoma

Angiomyolipomas (AMLs) are the most common mesenchymal renal neoplasms and are classified as neoplasms of perivascular epithelioid cells (PEComa). AML is usually a benign neoplasm arising most often in the kidney although it has been described in a wide variety of sites. Most patients are adults, and one-third suffer from tuberous sclerosis. We describe a case of renal AML in a 54-year-old Bahraini woman who presented to the Bahrain Defence Force Hospital with right flank pain and hematuria, and who was known to have rheumatoid arthritis but had no cutaneous or other stigmata of tuberous sclerosis. It is the largest AML reported in Bahrain and is also striking for the fact that it contained an intratumoral aneurysm that ruptured causing symptoms leading to the radiological diagnosis of renal mass. Furthermore, the occurrence of an aneurysm in sporadic AML, as in our case, is rare since the large majority tend to be seen in association with tuberous sclerosis.