Metastatic Breast Cancer Mimicking Small Bowel Crohnʼs Disease

Abstract

Introduction: Small bowel involvement of metastatic breast cancer is a rare but recognized entity. It can present in a number of ways and can often be confused with primary disorders of the gastrointestinal (GI) tract such as Crohn's disease. We present a case of metastatic breast cancer to the terminal ileum initially presenting as abdominal pain. Case: A 62 year old Caucasian female with metastatic breast cancer to bone presented with left lower quadrant pain for 6 months. The pain was dull without radiation and no aggravating or relieving factors. She complained of no other GI related symptoms such as constipation, diarrhea, nausea, vomiting, weight loss or blood in stool. There was no known family history of colon cancer or inflammatory bowel disease. Initial workup included a CT scan which showed nonspecific wall thickening of the terminal ileum. A small bowel follow through was subsequently done and revealed mucosal effacement and nodularity of the last 15 cm of the terminal ileum. A colonoscopy to the terminal ileum was then done. Endoscopically, the terminal ileum appeared grossly abnormal with several ulcerations and surrounding erythema and edema. The colonic mucosa appeared normal except for scattered diverticulosis. Biopsies of the terminal ileum revealed chronic inflammation. At that time the patient was suspected to have Crohn's disease but was not treated as she did not follow up with a gastroenterologist. One year later as she remained symptomatic, the patient's primary care physician referred her to a gastroenterologist for suspected Crohn's disease. She underwent repeat colonoscopy to confirm the diagnosis. Terminal ileal ulcers were again seen and biopsy results revealed metastatic breast cancer. Discussion: Breast cancer may metastasize anywhere within the GI tract. In one retrospective review, it was estimated that breast cancer metastasizing to the GI tract involved the small bowel in 19% of patients. The most common presentations that are reported are abdominal pain, obstruction and bowel perforation. The differential diagnosis of terminal ileal ulcers is broad. The most common etiologies are inflammatory bowel disease, infections and ischemia. However, metastatic breast cancer may affect the small bowel although it is rare. Clinicians should have a high index of suspicion in patients with metastatic breast cancer presenting with terminal ileal ulceration.