ANALYSIS OF THE CHARACTERISTICS OF INTESTINAL ENDOMETRIOSIS LESIONS WITH RECTAL INVOLVEMENT USING THREE-DIMENSIONAL ENDOANAL ULTRASOUND

Introduction Intestinal endometriosis represents a complex and challenging form of the condition, involving the gastrointestinal tract, particularly the rectum. Three-dimensional endoanal ultrasound provides detailed and precise images of endometriotic lesions in the rectum and is an important tool for the diagnosis and proper management of these patients.

Objective To evaluate the characteristics of endometriosis lesions affecting the rectum using three-dimensional endoanal ultrasound.

Method This is a retrospective study, with data obtained through the evaluation of electronic medical records of patients seen in the coloproctology service of a University Hospital. All patients were referred for rectal ultrasound evaluation due to suspected lesions from previous imaging studies (transvaginal ultrasound or magnetic resonance imaging). Patients underwent three-dimensional endoanal ultrasound from May 2017 to May 2024 using the Flex-Focus equipment from BK Medical. Patients with associated anorectal conditions, such as inflammatory bowel disease, anorectal cancer, or those who had previously received pelvic radiation, were excluded. The evaluated data included the location of the lesion, depth in the rectal wall, lesion length, and distance to the anal margin. The sample consisted of 69 patients with intestinal endometriosis, with 3 excluded because rectal involvement was not confirmed. Statistical analysis was performed using GraphPad Prism and Excel.

Results All lesions were found in the anterior hemicircumference of the rectum. The most common locations were the mid rectum (25) and upper rectum (27), with 8 lesions found in the lower rectum. Six patients had lesions in more than one segment. Of the 72 lesions found, most (39) affected the muscular layer of the rectum. Twenty-four involved the perirectal fat, 6 extended to the submucosa, and 3 reached the mucosal muscular layer. The mean length of the largest axis of the lesion in the longitudinal plane was 1.84 cm (0.37 cm–3.5 cm), and in the axial plane, the mean was 2.08 cm (1.12 cm–8.8 cm). The average distance of the lesions from the anal margin was 9.0 cm.

Conclusion Intestinal endometriosis lesions predominantly occur in the mid and upper rectum, approximately 9.0 cm from the anal margin, and most commonly affect the muscular layer of the rectum.

No conflict of interest has been declared by the author(s).

Publication History

Article published online:
25 April 2025