Objective  To explore the characteristics of abdominal wall endometriosis (AWE) on magnetic resonance imaging (MRI).

  Methods  The clinical and MRI data of 7 patients with pathologically confirmed AWE in Peking Union Medical College Hospital from January 2008 to January 2013 were retrospectively collected and analyzed.

  Results  Five of the AWE lesions were single and two were multifocal. Ten AWE lesions were found in 7 patients. Seven out of 10 lesions were located in the left, two in the middle, and one in the right. Five lesions were located in the subcutaneous tissue and fascia, the abdominal muscles were invaded in four lesions, and one was located in the subcutaneous tissue, fascia, and muscle. Endometrial invasion from the scar into the abdominal cavity was observed in two patients, with anterior wall and fundus of the uterus for one patient and anterior wall of bladder for another. Nine lesions were solid and mainly showed isointense or hyperintense signal on T1WI and T2WI compared with muscle with foci of higher intensity on T2WI. In one patient, a cystic hyperintense lesion was found on T1WI (including shading on T2WI). Coexistent abnormality was observed in five patients, including adenomyosis in two, uterine malformation in one, adenomyosis and uterine malformation in one, and fibroid in one patient.

  Conclusions  MRI manifestations of AWE can provide information on the anatomic locations and the lesion extension. Thus, MRI is an important method for preoperative examination and postoperative follow-up.