Perivesical abscess caused by migration of a fish bone from the intestinal tract

A 55-year-old woman was admitted to the Department of Urology at Chiba University Hospital. The patient's chief complaint was frequent urination and micturition pain. Computed tomography of the abdomen demonstrated a mass lesion in contact with the anterior wall of the bladder. Mass extirpation was performed transperitoneally. On dissection of the mass, a thin foreign body shaped like a skewer was detected. A specimen of the mass revealed non-specific inflammation. Elemental analysis with an electron probe microanalyser (EPMA) revealed that the composition of the foreign body was consistent with bone. The perivesical mass was diagnosed as an abscess caused by a fish bone that migrated from the intestinal tract.