A 61-year-old woman with a history of bilateral pyelonephritis and a nonfunctioning right kidney developed end-stage renal failure. She started chronic hemodialysis via a polytetrafluoroethylene dialysis fistula in the right lower arm in October 2006. Her medical history also included morbid obesity, type 2 diabetes mellitus, and a cholecystectomy. She was evaluated for a renal transplant. During this evaluation, she noted an expanding mass she had had for years on the left side just above the iliac crest. This mass gave intermittent episodes of muscular pain and a heavy feeling in the left flank. On clinical examination, we found that she had a body mass index (calculated as weight in kilograms divided by height in meters squared) of 41, classifying her as morbidly obese. She had reducible swelling with a diameter of approximately 10 cm in the left flank. The swelling increased in size with straining and Valsalva maneuver. There were no other abnormalities. The edges of the swelling were indistinguishable from the surrounding soft tissue on clinical examination. A computed tomographic scan of the abdomen revealed a protrusion of abdominal contents through the muscular layers of the lumbar region. This protrusion lay posterior to the oblique muscles of the abdomen, anterior to the quadratus lumborum muscle, and superior to the iliac crest (Figure 1 and Figure 2).