The American Journal of GASTROENTEROLOGY VOLUME 107 | SUPPLEMENT 1 | OCTOBER 2012 www.amjgastro.com Abstracts S358 diarrhea, malabsorption and weight loss. Diagnosis is established on intestinal biopsy with a subepithelial collagen layer greater than 10 mu and infamma- tory cells in the lamina propria. Evaluation for coexisting microscopic colitis should be performed. Diarrhea is classically unremitting without aggressive immunosuppression. Steroids are the mainstay of therapy along with GFD, with remission rates of up to 80%. However, the clinical course is unpredict- able and ofen poorly responsive to medical therapy. Early recognition of CS is essential to prevent signifcant morbidity and mortality. However, more data are needed to optimize therapeutic strategies. 871 Breast Metastasis as a Presentation of Ileal Carcinoid and the Importance of CDX-2 Staining Michael Greenspan, MD, Michelle Collier, MD, Ihab Lamzabi, MD, Paolo Gattuso, MD, Kateri Evans, RN, Shriram Jakate, MD, Sohrab Mobarhan, MD, FACG, Joshua Melson, MD, MPH. Rush University Medical Center, Chicago, IL. Introduction: Carcinoid of the breast is a rare entity and cases where an ileal carcinoid is diagnosed by presentation as a breast mass are extremely uncom- mon. We present a case of an ileal carcinoid that manifested as breast metasta- sis, review cases from our institution of primary breast carcinoid with CDX-2 staining, and discuss the difculty of diagnosis in these cases and the impor- tance of CDX-2 staining. Case Report: A 49-year-old woman presented to our institution for further management of a breast mass identifed as an infltrat- ing ductal carcinoma afer having undergone lumpectomy. Te pathology was reviewed and showed moderately diferentiated solid neuroendocrine carci- noma with ensuing staining positive for CDX-2. She then underwent EGD and colonoscopy, which showed a friable 3 cm semipendunculated terminal ileum mass with biopsy revealing infltrating well-diferentiated neuroendocrine tumor consistent with a gastrointestinal primary malignancy. She underwent right hemicolectomy with plans for octreotide therapy. Methods: We reviewed the database at our institution for cases from 2000 through 2010 of primary neuroendocrine carcinoma of the breast defned by WHO classifcation. All tumors were then stained for CDX-2 and patients’ charts were reviewed for gastrointestinal work-up. Results: Seven cases of primary neuroendocrine carcinoma of the breast were identifed. All tumors were negative for CDX-2 staining. Review of the 7 cases showed a negative work-up for gastrointestinal malignancy or no manifesta- tion of gastrointestinal malignancy following diagnosis of primary neuroendo- crine carcinoma of the breast. Conclusion: In addition to our case, there are only 7 cases reported in the lit- erature of an ileal carcinoid presenting as a breast mass. Our case highlights the complexity of this diagnosis, as neuroendocrine carcinoma is difcult to diferentiate histologically from invasive adenocarcinoma due to overlapping morphologic features. Te diagnosis is especially difcult, as exemplifed here, when there is no known history of carcinoid. Tere are also typically no clini- cally reliable features to distinguish the two entities as most do not present as a carcinoid syndrome. Review of the 7 other cases at our institution of primary neuroendocrine carcinoma of the breast illustrates the importance of CDX-2 staining in work-up of these tumors. Breast neuroendocrine carcinoma should be considered when there are possible neuroendocrine features present, which can be confused with breast carcinoma. It should also prompt CDX-2 staining of these tumors, which, if positive, suggests a primary tumor outside the breast and should lead to gastrointestinal assessment including endoscopic evaluation. 872 Serum-Negative, Site Specifc HHV-6 Infection Causes Nausea and Vomiting Following Double Umbilical Cord Stem Cell Transplantation Kati Glockenberg, MD, 1 Carl Crawford, MD, 1 Fouad Otaki, MD 2 . 1. New York Presbyterian/Weill Cornell Medical Center, New York, NY; 2. Stamford Hospital / Columbia University College of Physicians and Surgeons, Stamford, CT. Purpose: Current literature describes similar clinical manifestations between human herpes virus 6 (HHV-6) infection and graf versus host disease (GvHD) in post-hematopoietic stem cell transplant (HSCT) recipients. Terefore, it is essential to consider HHV-6 infection in patients with gastrointestinal (GI) symptoms suggestive of GvHD. We present a case that highlights the impor- tance of testing gastroduodenal tissue as an adjunct to serological testing of HHV-6 in this patient population. A 30-year old woman (HHV-6 IgG +) with acute lymphocytic leukemia (ALL) presented for a double umbilical cord stem cell transplant with myeloablative conditioning. Her post-transplant course was complicated by late engrafment, Klebsiella pneumoniae sepsis, BK cysti- tis, HHV-6 viremia and biopsy-proven stage 4 GvHD of the upper and lower GI tract associated with fever, abdominal pain, diarrhea and vomiting. She was treated with 3 months of high dose steroids for GvHD and one month of a combination of IV foscarnet and oral valganciclovir for HHV-6 reactivation (viral load 66,292 cpy/ml). Her symptoms improved (viral load undectable), but she then returned to the hospital day + 150 post transplant for dehydration secondary to persistent nausea and vomiting. Serum PCR testing for HHV- 6 and gastroduodenal biopsies for GvHD were negative. However, PCR of gastroduodenal tissue biopsies for HHV-6 was positive (viral load 5,912 viral copies/1,000 cell equivalent). She was restarted on valgancyclovir for 4 weeks and had total resolution of her symptoms at the end of this time. HHV-6 is a lymphotrophic virus which belongs to the β-herpesviridae family. It typically remains latent in certain host cells but can reactivate in immunocompromised patients. In HSCT recipients, gastrointestinal complications of HHV-6 may include abdominal pain, nausea, vomiting, diarrhea, cholestasis and hepati- tis which mimics and can worsen the grade of GvHD. Cord blood transplant recipients and previous episodes of GvHD are found to be predictors of HHV- 6 reactivation, as was seen in our patient. Tis case highlights that HHV-6 vire- mia need not be synchronous with a site-specifc infection in HSCT patients with upper GI symptoms. Given the prevalence and correlation between GI manifestations of HHV-6 and GvHD, isolated local infection should be con- sidered in the diferential diagnosis of persistent GI symptoms despite serum- negative HHV-6 testing. Te clinical beneft of treating biopsy-proven HHV-6 of the GI tract should be further studied in patients with and without GvHD post-HSCT. 873 Metastatic Small Intestinal Adenocarcinoma Mimicking Advanced Ovarian Carcinoma Cherif Abdelmalek, MD, 1 Qi Shi, MD, 1 Sathyanarayanan Ramakrishnan, MD, 1 Lisa Tomas, MD 2 . 1. Te Wright Center for Graduate Medical Education, Scranton, PA; 2. Hematology and Oncology Associates of Northeastern Pennsylvania, Scranton, PA. Introduction: Primary malignant neoplasm of the small intestine is extremely rare, accounting for only 1-3% of all malignancies of GI tract. Common meta- static sites of small intestinal cancer are regional lymph nodes and liver. We report an unusual case of small intestinal adenocarcinoma which mimicked an advanced ovarian carcinoma at presentation. Case Presentation: A 46-year-old female was admitted for elective laparoscopic cholecystectomy procedure for a 3 month history of abdominal pain. Obstruction series and CAT scans of the abdomen and pelvis showed questionable focal small bowel obstruction. At the time of the procedure, examination of the peritoneum revealed multiple peritoneal and omental lesions. Frozen section pathology of one of the perito- neal lesions confrmed adenocarcinoma. Given her clinical presentation and operative fndings, an ovarian carcinoma diagnosis was presumed. She subse- quently underwent exploratory laparotomy, radical tumor debulking, perito- neal stripping, total abdominal hysterectomy, bilateral salpingo-oopherctomy, small bowel resection with reanastomosis, excision of abdominal implants and appendectomy. Postoperative pathology revealed moderately diferentiated adenocarcinoma. Tere was intestinal involvement with full thickness of bowel wall and extension to surrounding fat and serosa. Metastatic adenocarcinoma was also found in omental, pelvic mass biopsies, adnexa bilaterally, uterine serosa and myometrium, and periappendicular fat. Immunohistochemistry showed positive reactivity for CK20 and CDX2 and negative for CK7 suggest- ing a bowel origin rather than ovarian primary. A clinical diagnosis of stage IV small bowel adenocarcinoma was made. Te patient had no evidence of residual disease post-operatively. She was treated adjuvantly with FOLFOX/