S4079 Case of Cecal Endometriosis a Diagnostic Challenge That Requires a Multidisciplinary Approach

Introduction: Endometriosis is the existence of endometrial tissue implants outside of the uterus that can occur on other solid organs within the body. Endometriosis most commonly occurs within the rectosigmoid junction within the bowel and only occurs 2%-5% of the time within the cecum. The symptoms of endometrial implants within the bowel can present as chronic abdominal pain, hematochezia, constipation, diarrhea, dyspareunia. We present a case of cecal endometriosis masquerading as a colonic tumor in appearance. Case Description/Methods: A 46-year-old woman with a past medical of endometriosis s/p hysterectomy, chronic constipation who initially presented to the hospital for evaluation of abdominal in the lower left quadrant. During her hospitalization she had a computed tomography abdomen/pelvis with contrast that showed a cecal mass. Subsequently, she underwent a colonoscopy that showed a thickened fold in the cecum that was biopsied revealing colonic mucosa with mild chronic active colitis. Patient was discharged to follow up with gastroenterology and hepatology for magnetic resonance imaging (MRI) abdomen with and without contrast to further evaluation of her cecal mass. She underwent an MRI abdomen with and without contrast that revealed a persistent mass like abnormality in the right lower quadrant and hepatic adenoma. She then underwent a positron emission tomography scan to further evaluate the lesion that noted a hypermetabolic mass in the right lower quadrant that was suspicious of being a small bowel neuroendocrine tumor or gastrointestinal stromal tumor (GIST). Patient then followed up with general surgery for an exploratory laparotomy with ileal resection, partial colectomy with primary anastomosis for mass of the cecum. After the mass was resected they found it to be consistent with endometriosis and mass in the segment VII of the liver. Discussion: Our patient has a known history of endometriosis that had previously been diagnosed and treated with a laparotomy and hysterectomy. Our case is unique as the patient had recurrent endometriosis presenting in the cecum. Initially it was a diagnostic challenge that was unable to be diagnosed without surgery and was concerned to be a GIST or neuroendocrine tumor. Our patient had non specific bite on bite biopsies showing inflammation but did not reveal the diagnosis. Despite patient's subsequent imaging the final diagnosis was ultimately made due to histopathologic analysis after surgical resection. It is important to recognize the diagnostic challenge of recognizing cecal or bowel endometriosis given it’s low occurrence.