Unusual perirenal location of a tailgut cyst

The authors describe a case in which a tailgut cyst occurred at an unusual location in a 22-year-old woman referred for abdominal discomfort and urinary frequency. The left abdomen contained a palpable mass, found at imaging studies to be a homogeneous, unilocular and cystic, and anterior to the left kidney. After surgical excision, it was shown to be a tailgut cyst.