Endometriosis of the rectum: CT findings

Objective To investigate the CT manifestations of recto-endometriosis. Methods Three pathologically proved cases of recto-endometriosis were reported, the CT features and clinical manifestations were investigated retrospectively with review of literatures. Results The patients were all menstruating females (28, 34, and 45 years old, respectively), and anal pain emerged during menses in one case. Rectal examination revealed stiff immobile mass along the rectal wall in all three cases. All the cases showed solid masses on CT scan with moderate enhancement after contrast administration. Two of them confined to the rectal walls, another involved the rectum and peri-rectal aspect. One case was misdiagnosed as well-differentiated adenocarcinoma of rectum in frozen section by biopsy specimen.Conclusion A solid mass was always found in recto-endometriosis. No characteristic CT feature was manifested. Attention should be paid to the differentiation from rectal tumors when making the diagnosis.