S2454 Endometriosis With a Colonic Focus: A Rare Case of Cecal Endometriosis

Introduction: Endometriosis, which is seen in about 4%-17% of all menstruating women, is defined by the presence of endometrial tissue outside the uterine cavity. Extra-pelvic manifestations within the gastrointestinal tract can occur; however, cecal involvement is rare and reported in only about 3.5% of bowel endometriosis cases. Furthermore, signs and symptoms commonly mimic other entities, making diagnosis particularly challenging. Here, we present a rare case of asymptomatic cecal endometriosis detected on screening colonoscopy. Case Description/Methods: A 46-year-old woman with a past medical history of dysmenorrhea and uterine fibroids presents for her first screening colonoscopy. Endoscopic examination demonstrated a sub-mucosal medium-sized mass arising from the appendiceal orifice. Diagnosis was attempted with bite-on-bite biopsy. However, pathology revealed mild nonspecific inflammatory changes without evidence of malignancy. Follow-up CT imaging of the abdomen showed localized thickening of the cecum. The patient was referred to colorectal surgery and underwent a laparotomy which revealed a 1.8 cm x 1.3 cm x 1.2 cm firm mass at the ileocecal junction. The lesion was subsequently resected with creation of an ileocolic anastomosis. Biopsy of the resected mass returned with findings consistent with endometriosis involving the ileocecal mucosa and muscularis propria (Figure 1). Discussion: Bowel endometriosis rarely manifests at the cecum, as the rectosigmoid and proximal colon are involved in more than 90% of cases. Presenting symptoms may include abdominal pain, vomiting, and diarrhea; however, our patient was completely asymptomatic. Due to nonspecific clinical presentations and imaging findings, patients are often mis-diagnosed with other disorders including colitis, diverticulitis, and malignancy. As such, histopathological examination of tissue is crucial for differentiation. Clinicians should be cognizant of these challenges in diagnosing bowel endometriosis, as a delay may potentiate into life-threatening complications including bowel obstruction and emergent surgical intervention.Figure 1.: A and B: Pathology of resected ileocecal mass revealing presence of endometrial glands and stroma within ileocecal mucosa and muscularis propria.