1507 A Rare Case of Intestinal Endometriosis Mimicking Acute Appendicitis and Sigmoid Malignancy in a Five Year Time Span

INTRODUCTION: Endometriosis is characterized by implantation of endometrial epithelium outside the uterus. The prevalence is about 10-15% in women of reproductive age. The most common extra-pelvic site is the GI tract, affecting 4–37% of women with endometriosis. The sigmoid colon and rectum are the most common sites followed by the ileum, appendix and cecum. CASE DESCRIPTION/METHODS: Here we present a very rare case of severe intestinal endometriosis involving multiple GI sites including the terminal ileum, appendix and recto-sigmoid colon in the past 5 years. 4.5 years ago, the then 27 year old otherwise healthy female presented with worsening RLQ pain. She had leukocytosis of 15K WBC with CT scan showing a dilated and thickened distal appendix consistent with appendicitis. She underwent laparoscopic appendectomy without complications. Pathology reported endometriosis (Figure 1). After appendectomy, she continued to have diffuse abdominal pain with nausea and constipation. As part of GI workup, she underwent EGD and colonoscopy about 3 years ago with findings of two recto-sigmoid strictures with biopsies showing endometriosis. The patient was then lost followup until she was readmitted with multiple GI complaints including nausea/vomiting, abdominal pain, with alternating diarrhea and constipation. It appears that she had been treated for IBS and also received hormonal treatment for endometriosis in the past two years. On admission, she had leukocytosis of 16K and a CT scan showing a 3 cm focal apple-core lesion in the distal sigmoid colon. Colonoscopy showed a very severe stricture at the distal sigmoid colon with nodular mucosa in the proximal rectum. Pathology was negative for malignancy or endometriosis. She then underwent laproscopy with findings of 2 strictures in the recto-sigmoid colon together with another stricture 5 cm proximal to the IC valve in the distal ileum. Partial resection of the recto-sigmoid colon together with a right hemicolectomy was performed. Pathology of both TI and recto-sigmoid colon showed endometriosis (Figure 2). During the one-month post-op followup, she reported resolution of constipation. DISCUSSION: Our patient represents a rare case of symptomatic multi-focal gastrointestinal endometriosis with mucosal involvement at different times mimicking appendicitis and sigmoid malignancy. Endometriosis should be considered in the differential diagnosis in any young woman with lower GI symptoms.