2044 Metastatic Breast Cancer: Another Crohn’s Mimic?

Abstract

INTRODUCTION: In the US, breast cancer (BC) is the 2nd most common cancer diagnosed in women. Approximately 30% of women diagnosed with BC develop metastatic disease. Usually, it spreads to the liver, brain, bones and lungs; rarely it spreads to the GI tract. We present a case of metastatic breast cancer (MBC) to the GI tract that initially mimicked Crohn’s disease. CASE DESCRIPTION/METHODS: A 66 yo female with a history of right-sided, invasive, lobular BC, s/p lumpectomy, radiation, and adjuvant hormonal therapy presented to her physician with complaints of irregular bowel habits and reflux. An EGD revealed a hiatal hernia and inflammation of the antrum with normal biopsies. A colonoscopy revealed abnormal rectal mucosa with edema, friability and narrowing; biopsies showed prolapse-type changes. Due to progressive and worsening symptoms, a flexible sigmoidoscopy was done. This revealed raw and inflamed tissue in the distal rectum with severe stricturing, requiring dilatation. Repeat biopsies were unremarkable. Crohn’s disease was in the differential as the responsible etiology for the rectal stricture; thus, an MR enterography was done. Multiple skip lesions throughout the GI tract, consistent with Crohn’s disease, were demonstrated and mass-like thickening (without inflammatory changes) in the antropyloric region was also evident (Figure 1). EGD/EUS revealed pyloric stenosis with a thickened and edematous pylorus and duodenal bulb (Figure 2), and hypoechoic tissue in the muscularis propria of the distal antrum/pylorus. FNA and mucosal biopsies were nondiagnostic. Repeat colonoscopy demonstrated a significant distal rectal stricture without mucosal abnormalities. Repeat biopsies, this time, demonstrated poorly differentiated MBC with IHC staining consistent with the patient’s previous lobular mammary carcinoma (Figure 3). The patient subsequently underwent an ex-lap gastrojejunostomy and was found to have a large bulky mass on the serosal surface of her pylorus and duodenum. She is currently on salvage therapy for MBC. DISCUSSION: Our case demonstrates that diagnosing MBC to the GI tract may prove evasive. In a patient with a history of BC and persistent/worsening GI symptoms, it is imperative that one keeps the differential broad and includes MBC to the GI tract as a real possibility. Early endoscopic evaluation with biopsies and appropriate IHC staining of samples should be performed in suspected cases. MBC should be on the list of etiologies that can mimic Crohn’s disease.