S3147 Diagnosing Sigmoid Endometriosis by EUS-fine needle biopsy

Introduction: Endometriosis is a common cause of chronic abdominal pain, among other symptoms, in reproductive-age women. Typically, this condition is either diagnosed clinically based on history, exam, and imaging, or via surgical visualization or biopsy. In this report, we describe a case of endometriosis in an asymptomatic woman diagnosed by fine-needle biopsy (fine needle biopsy) via endoscopic ultrasound (EUS) of a sigmoid colon sub-epithelial lesion noted incidentally during screening colonoscopy. Case Description/Methods: A 48-year-old woman with no significant medical history underwent colonoscopy for colorectal cancer screening. During colonoscopy, 2 partially obstructing sub-epithelial lesions were found in the sigmoid (Figure 1) and descending colon. Cold forceps biopsies of the lesions were significant for ischemic-type injury with regenerative changes. A computed tomography (computed tomography) scan of the abdomen and pelvis with IV contrast demonstrated sigmoid colon thickening. Subsequent endoscopic ultrasound exam of the sigmoid lesion was done which showed a 4.0 cm x 2.9. cm hypoechoic, heterogenous lesion involving the fifth and fourth layers (serosa and muscularis propria), and fine needle biopsy was performed. Pathology showed endometrial glands and stroma with positive CD10, ER, pax8, and CK7 immunostains consistent with endometriosis, and the patient was referred to gynecology for further management. Discussion: Endometriosis is a condition in which endometrial tissue is present outside of the uterine cavity. This disease affects about 10% of reproductive-age females and is a common cause of chronic abdominal pain, among other symptoms, and causes significant morbidity. Symptoms are non-specific which can lead to a delay in clinical diagnosis of 10 years or more. Definitive diagnosis is historically accomplished via laparoscopic surgery, which is invasive and can be frightening for patients. This case demonstrates an uncommon presentation of endometriosis with involvement of the colonic wall. Due to the extrinsic nature of the lesion, endoscopic biopsies are usually diagnostic and EUS guided transmural sampling can help with establishing diagnosis and exclude other neoplastic lesions. There have been other case reports with similar results. Therefore, in patients with imaging suggestive of endometriosis involving the colon, particularly in areas reachable by EUS, EUS with fine needle biopsy should be considered to confirm the diagnosis and ultimately help guide management.Figure 1.: Sigmoid Colon Sub-Epithelial lesion.