Background: No study has systematically investigated the colonoscopic findings and histologic diagnostic yield in the diagnosis of colorectal endometriosis.
Objectives: We classified the colonoscopic features of colorectal endometriosis and determined the diagnostic yield of endoscopic biopsy in relation to endoscopic subtypes of colorectal endometriosis.
Methods: A total of 17 patients with colorectal endometriosis were assessed. The data from the colonoscopic and histologic assessments made between November 1994 and October 2009 were retrospectively analyzed in single tertiary referral teaching hospital.
Results: Colonoscopy showed eccentric wall thickening in 14 patients (82%) and polypoid lesions in 3 patients (18%). Surface nodularities were noted in 11 of the 14 patients (79%) with eccentric wall thickening, and in 1 of the 3 patients (33%) with polypoid lesions. The overall histologic diagnostic yield was 47% (8 of the 17 patients). The rate of histologic confirmation was higher in patients with surface nodularities (8 of the 12 patients, 67%) versus those without (0 of the 5 patients, 0%) surface nodularities (P=0.02).
Conclusions: Eccentric wall thickening is the most common colonoscopic finding of colorectal endometriosis, and the histologic diagnostic yield of endoscopic biopsy is high when lesions are accompanied by surface nodularities.