An 1-year-4-month-old girl presenting with anemia and drowsiness was admitted to theCenter. A fist-sized tumor was palpated at the lower abdomen. An emergency laparotomy revealed hemoperitoneum caused by intraabdominal rupture of the tumor of the abdominal wall. The tumor was resected en-mass, and is suspected to have urachal origin. Urachal sarcoma reported in the English and Japanese literature were 17 cases. It differs extraordinarilly from urachal carcinoma or any other neoplasms. The main symptoms are abdominal mass and abdominal pain. Two out of 17 cases reported survived more than two years after operation. Four basic criteria to satisfy the identification of urachal sarcoma, regarding it's localization, extention and histology were proposed and discussed.
