P1243 - Call the Gastroenterologist, It's Breast Cancer

Eyad Z. Gharaibeh, MD, John W. Finnie, MD
Mercy Hospital St. Louis, St. Louis, MO

Introduction: Infiltrating lobular carcinomas are the second most common type of invasive breast cancer after invasive ductal carcinoma. Lobular carcinomas metastasize in unpredictable invasion patterns and can present atypically, making early detection and successful management a challenging problem for clinicians. Despite the high incidence of invasive lobular breast carcinoma, few cases of metastasis to the right ascending colon have been reported in the literature.

Case Description/Methods: A 58-year-old female presented with an abnormal sensation in her left breast. Lumpectomy and axillary lymph node dissection revealed oligometastatic estrogen receptor (+) lobular carcinoma. PET scan showed no distant metastasis, however, her decision to undergo prophylactic total abdominal hysterectomy & bilateral salpingo-oophorectomy (TAH-BSO) led to detection of an incidental ovarian metastasis on histologic examination. The patient then underwent chest wall radiation with subsequent hormone-based chemotherapy (Anastrozole & Letrozole), successfully achieving a state of remission. Eight years later, a supraclavicular lymph node appeared with neck node biopsy revealing recurrent disease with loss of ER expression. Restaging CT scan revealed circumferential thickening in the ascending colon. Clinically, the patient only complained of intermittent abdominal cramps without melena or hematochezia. Colonoscopy revealed notable ascending colon wall thickening and luminal narrowing but without mucosal/intraluminal dysplastic/neoplastic appearance. Biopsy of benign appearing colon polyps was notable for deposits of metastatic lobular breast carcinoma. Given this isolated area of highly symptomatic disease, she underwent right hemicolectomy. A novel treatment paradigm with the immunotherapy Atezolizumab, combined with nanoparticle albumin bound paclitaxel, is planned as her next step in management.

Discussion: Our case demonstrates how patients with colonic metastasis of lobular carcinoma may have a mild clinical presentation that undermines the true severity of the underlying disease. The bland appearance of the colon and vague thickening contrasted with the surprising finding of not only diffuse replacement of 44 out of 45 lymph nodes, but also quite extensive replacement of the colonic parenchyma with metastatic lobular breast carcinoma. Clinicians managing patients with lobular carcinoma should maintain a high level of suspicion when encountering mild abnormalities on imaging or patient reported gastrointestinal symptoms.


Figure: Figure 1: Coronal CT image showing focal circumferential thickening of the ascending colon about 4.5 cm in length.
Figure 2: Colonoscopy revealing benign appearing colonic polyps in the ascending colon (A) and hepatic flexure (B).


Disclosures:
Eyad Gharaibeh indicated no relevant financial relationships.
John Finnie indicated no relevant financial relationships.


Eyad Z. Gharaibeh, MD, John W. Finnie, MD. P1243 - Call the Gastroenterologist, It's Breast Cancer, ACG 2021 Annual Scientific Meeting Abstracts. Las Vegas, Nevada: American College of Gastroenterology.