Hindawi Publishing Corporation Case Reports in Medicine Volume 2009, Article ID 564756, 3 pages doi:10.1155/2009/564756 Case Report Occult Breast Carcinoma Presenting as Gastrointestinal Metastases Lonzetta Neal, Nicole Sookhan, and Carol Reynolds Divisions of General Internal Medicine Breast Diagnostic Clinic, and Pathology, Department of Surgery, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA Correspondence should be addressed to Lonzetta Neal, neal.lonzetta@mayo.edu Received 7 August 2009; Accepted 28 October 2009 Recommended by Sarkis Meterissian Occult breast cancer has frequently been described as presenting as axillary lymph node metastases but rarely as gastrointestinal metastases, Varadarajan et al. (2007). In extremely rare situations, cancerous lesions identiﬁed in the gastrointestinal tract have been determined to be metastatic lesions from primary breast cancers, Taal et al. (2000). We report a case of an occult lobular adenocarcinoma presenting as gastrointestinal metastases. It is essential that the possibility of lesions found in the gastrointestinal tract originating from distant or occult cancers be considered in order that appropriate therapeutic options may be discussed and considered early after diagnosis. Copyright © 2009 Lonzetta Neal et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. 1. Introduction Breast carcinoma is the most common malignancy in women after skin cancer and, after lung cancer, the most frequent cause of cancer death in females. Over 175,000 women were diagnosed with breast cancer in 2007 and more than 40,000 died from the disease. With advancements in screening over the past 25 years, fewer than ten percent of patients will present with metastatic breast carcinoma at the time of diagnosis. However, despite improvements in surgical and chemotherapeutic therapies, women with early-stage and locally advanced breast cancer relapse not infrequently, usually presenting with distant metastatic disease. Metastatic disease of breast cancer origin commonly appears in the skeleton (43%), stomach (27%), lung (8%), and liver (4%) [1]. Occult breast cancer (OBC) can rarely manifest as axillary nodal metastases with an incidence of 0.3% to 1% [2], and, of those female patients presenting with adeno- carcinoma within an axillary lymph node, breast cancer is most likely the primary source [3]. Gastrointestinal (GI) tract metastasis and carcinomatosis from primary breast cancer are rare. Data from two series, including surgical and autopsy specimens targeting the gastrointestinal tract, reported metastatic breast cancer occurred in this site at a rate of 8% to 35% [4, 5]. Our review of the literature revealed one case report of occult breast carcinoma presenting as a pancreatic tumor [6]. We report a case of an occult breast cancer presenting with gastrointestinal metastasis. 2. Background 2.1. Case Report. A 53-year-old female presented to an outside institution with a one-month complaint of abdom- inal pain. An extensive evaluation was only remarkable for an umbilical hernia and a chest wall nodule. The chest wall nodule was excised and reported as benign. Screening colonoscopy was negative except for a reportedly benign colon polyp that was removed. She underwent an umbilical hernia repair with mesh placement. Her postoperative course was complicated by omental herniation under the mesh with omental infarction and intraperitoneal bleeding. She underwent repair of this process but continued to feel anorexic and ill. Five months following her initial operation, she developed borborygmi associated with watery diarrhea occurring up to ten times a day. An upper gastrointestinal endoscopic study with biopsies of the antrum was performed. No evidence of H. pylori or celiac sprue was noted. The biopsy revealed metastatic