P2048 - An Unusual Presentation of Breast Cancer in the Gastrointestinal Tract

Joseph Gooch, PA-C¹, Chris Moreau, BSBME², Richard Fazio, MD¹, Shazli Malik, MD³, Hari Sayana, MD, MBBS^1
1University of Texas Health Science Center at San Antonio, San Antonio, TX; ²UT Health San Antonio, San Antonio, TX; ³Pathology Associates of San Antonio, San Antonio, TX

Introduction: Breast cancer is the leading cause of cancer in women, and the second most common cause of cancer deaths in women due mostly to metastasis. The gastrointestinal (GI) tract is an infrequent location for metastasis, with rates in the range of 5 to 18%. Of those metasteses reported, intestinal metasteses accounted for less than 100 cases in a recent systematic review. We report on the unique finding of multiple GI tract metasteses of breast cancer found on routine endoscopic biopsy.

Case Description/Methods: A 55 -year-old woman with a history of breast cancer who was 1-year status post left mastectomy and on maintenance immunotherapy was referred for evaluation. The patient presented with a history of acute on chronic abdominal pain, diarrhea, and intermittent rectal bleeding, and was recommended for endoscopy including esophagogastroduodenoscopy (EGD) and colonoscopy. EGD revealed mild gastritis and random biopsies of the stomach were taken to rule out h. Pylori. Colonoscopy revealed two 5mm rectal polyps which were removed and sent for histopathology. Both gastric and rectal specimens showed evidence of infiltrative poorly differentiated adenocarcinoma consistent with metastatic breast signet ring carcinoma. Immunostains CK7, CK20, GATA 3, and Villin were performed with positive CK7 and GATA 3 stains. The patient was referred back to her current oncologist for follow-up and subsequent care.

Discussion: Though rare, it is still important to maintain a high index of suspicion for metastatic breast cancer involving the GI system in patients with new onset of GI symptoms who have a history of breast cancer. Quality endoscopic screening and surveillance should be a priority in these patients. The findings seen in our patient strengthen the argument for a thorough workup in these patients, regardless of their remission status.


Figure: Figure 1: 20X Magnification of Histopathology Slides
A: Signet ring cell carcinoma in rectal mucosa H&E
B: Signet ring cell carcinoma in gastric mucosa H&E
C: Positive staining for CK7 in tumor cells
D: Negative staining for CK20 in tumor. Overlying rectal mucosa is positive
E: Immunostain for GATA3 positive in tumor cells
F: Mucicarmine stain positive in tumor cells


Disclosures:
Joseph Gooch indicated no relevant financial relationships.
Chris Moreau indicated no relevant financial relationships.
Richard Fazio indicated no relevant financial relationships.
Shazli Malik indicated no relevant financial relationships.
Hari Sayana indicated no relevant financial relationships.


Joseph Gooch, PA-C¹, Chris Moreau, BSBME², Richard Fazio, MD¹, Shazli Malik, MD³, Hari Sayana, MD, MBBS¹. P2048 - An Unusual Presentation of Breast Cancer in the Gastrointestinal Tract, ACG 2021 Annual Scientific Meeting Abstracts. Las Vegas, Nevada: American College of Gastroenterology.