Primary Superior Lumbar Hernia with Nephrotic-range Orthostatic Proteinuria

Lumbar hernias are extremely rare. The posterolateral abdominal wall has two susceptible areas - the superior (Grynfeltt-Lesshaft's triangle) and the inferior (Petit's triangle) lumbar triangles - that cause superior and inferior lumbar hernias, respectively. We herein report a 67-year-old woman with nephrotic-range proteinuria caused by primary superior lumbar hernia. Superior lumbar hernias should be considered as a differential disease causing massive orthostatic proteinuria in adults. The present case highlights the importance of considering lumbar hernia in patients with flank swelling and the potential complications that may result from a missed diagnosis.