Catamenial rectal bleeding due to invasive endometriosis: a case report.

BACKGROUND: Although gastrointestinal involvement is the most common site for extra-genital endometriosis, deep infiltrative endometriosis, which affects the mucosal layer, is very rare. CASE PRESENTATION: We present a case of a 41-year-old white woman with cyclic rectal bleeding. Magnetic resonance imaging was done, together with colonoscopy and histologic staining of biopsied samples, which led to the final diagnosis of intestinal invasive endometriosis with recto-sigmoid stricture. Our patient was treated symptomatically with stool softeners. CONCLUSION: This case provides a rare example of catamenial bleeding. It is important to keep invasive endometriosis on the differential diagnosis whenever a premenopausal woman has cyclical rectal bleeding.