Crohnʼs Disease Masquerading Ileal Signet Ring Cell Carcinoma: Case Report

Abstract

Introduction: Signet ring cell carcinoma (SRCC) is a rare highly malignant adenocarcinoma that mainly originates in the stomach. Small bowel malignancies are rare, accounting for only 3% of all gastrointestinal tract neoplasms. We report a case of SRCC of the terminal ileum (TI) that was masqueraded by the presence of Crohn's disease (CD). Case Presentation: A 67-year-old man with a 49 year history of ileal CD, symptomatically controlled with Mesalamine, had recent changes in bowel habits. Endoscopy revealed normal-appearing colon and proximal ileal stricture at 10-15 cm from the Ileocecal valve. Six months later, computed tomography enterography demonstrated 2 long segments of ileal wall thickening and enhancement, suspicious of active disease. Over the next 4 months, he continued to have intermittent attacks of abdominal cramping, bloating, and borborygmus. He was treated with oral prednisone for suspected partial inflammatory small-bowel obstruction. Due to lack of improvement and weight loss, he underwent laparoscopic ileocecectomy with ileocolic anastomosis. Histopathological demonstrated 2.5 cm mucin-producing, moderate/poorly differentiated ileal adenocarcinoma with signet ring cell features as well as 6 cm tubulovillous adenoma in the setting of active stricturing CD. Unfortunately, the tumor was metastatic, and chemotherapy was initiated. Discussion: Adenocarcinomas represent 25-40% of small bowel neoplasms and may be associated with longstanding inflammation. It is extremely rare for SRCC to originate from the TI. It is likely that in our patient, SRCC arose, in part, because of longstanding inflammation due to CD. Routine screening for small bowel malignancies should be considered in patients with CD even with symptomatic remission. Aggressive medical therapy (i.e. biologics) to control subclinical inflammation may be warranted.