Endometriosis of the abdominal wall: ultrasonographic and Doppler characteristics

To describe the sonographic and clinical features of abdominal wall endometriosis (AWE), a frequently misdiagnosed condition.

This was a retrospective study of 21 consecutive women with pathologically proven endometriosis of the abdominal wall. Ultrasonographic and Doppler examinations were performed, before surgery, with a high-frequency linear transducer. The clinical data and the results of the sonographic examinations were reviewed and described.

At ultrasound, all the nodules appeared as discrete solid masses that were less echogenic than the surrounding hyperechoic fat. The nodules had a median diameter of 20 (range, 5-50) mm and in 18/21 (86%) cases the nodules had a round/oval shape. In eight of 21 (38%) women the AWE was located at the umbilicus, in six of 21 (29%) it was between the transverse suprapubic line and the umbilicus, in five of 21 (24%) it was found along the scar of a previous Cesarean section and in two of 21 (9%) it was in the right inguinal canal. The content was homogeneously hypoechoic in 12/21 (57%) women and inhomogeneous in the other nine (43%). The outer borders were invariably ill defined. Scarce blood vessels were found by power Doppler. Cyclic or continuous spontaneous pain at the level of the AWE was present in 19/21 (91%) cases, and two (9%) patients were asymptomatic.

Hypoechoic round/oval nodules with ill-defined borders and a hyperechoic rim should raise the suspicion of abdominal wall endometriosis, even in patients with no history of endometriosis or previous laparotomic surgery. Pressing the ultrasound probe against the nodule should reinforce a suspected diagnosis because of the pain it induces.