[An abdominal tumor of unusual nature. Synovial cyst in the iliopsoas bursa].

The authors report a case of tumour of the right iliac region in a 14 years old girl, disclosed by a light traumatism, without appreciable antecedents, nor locomotor disfunction. Ultrasonography and computed tomography showed its cystic constitution. Surgically, there was a synovial cyst of the ilioinguinal area, cyst of the iliopsoas bursa, with a hip joint communication. It was resected and a partial recurrence occurred, corrected surgically three years later. A recent MRI showed the spontaneous development of a same cyst on the left side, asymptomatic at all. A non exhaustive survey of literature confirmed the iliopsoas synovial bursa is uncommonly pathologic, but a constant natural formation in man. Pathology occurs only in over sixty years old adults. This case seems to be the first pediatric case. The cyst of the psoas bursa is generally revealed by an inguinal swelling; abdominal growing is rare. Imaging with ultrasonography, computed tomography and RMI such as in this case, showed the cyst issued between the coxofemoral joint and the iliac psoas terminal tendon. It can grow in a retroperitoneal way. Pathogenic hypothesis are debated. In this bilateral case, etiology evoke an anatomic anomaly, in relation a joint communication.