Distinct Appearances of Colonic Breast Cancer Metastases in a Single Patient

Abstract

Introduction: We present the case of a 71-year-old female who was admitted for hematochezia. She was diagnosed with metastatic ER+/PR+, HER2 non-amplified lobular breast carcinoma 3 years prior to admission. She was treated with modified radical mastectomy and adjuvant doxorubicin and cyclophosphamide, followed by paclitaxel and radiation, then abraxane and anastrozole. She was then started on eribulin and neulasta. She had a colonoscopy 4 years prior, demonstrating diverticulosis and hemorrhoids. Admission vital signs were stable. Hemoglobin was 10.1 g/dL. Colonoscopy was performed on hospital day #2. No bleeding was visualized on colonoscopy. Multiple non-bleeding, punctate, erythematous lesions were seen in the ascending colon (Figure 1 [1]). The descending and sigmoid colon demonstrated white nummular lesions, similar in appearance to colonic lymphoid aggregates (Figure 1 [2]). Biopsies of both sites demonstrated infiltrating poorly differentiated adenocarcinoma (Figure 1 [3 and 4]). Immunohistochemical findings were consistent with metastatic breast carcinoma.Figure 1Discussion: Breast cancer metastasis to the colon is rare, though some series show rates up to 12%. One autopsy study found 10 cases in over 16,000 autopsies, a rate of 0.06%. Breast carcinoma is the most frequent source of hematogenous metastases to the colon. Of the subtypes of breast cancer, infiltrating lobular carcinoma, as in our patient, has the highest rate of metastasis to the GI tract. Gastrointestinal metastases occur in the stomach most commonly due to the more robust vascular supply. Metastases have been reported from the tongue to the rectum. The endoscopic appearance of metastatic breast cancer in the colon is varied, with reports of fungating masses, diffuse thickening of folds, nodular lesions, and even ulcerated lesions similar in endoscopic appearance to inflammatory bowel disease. Our case demonstrates 2 distinct endoscopic appearances of diffuse colonic breast cancer metastases in one patient: punctate erythematous lesions in the right colon and diffuse nodular lesions in the left colon. Gastrointestinal metastasis should be considered in any patient with breast cancer presenting with gastrointestinal bleeding; any mucosal abnormalities visualized on endoscopy should be biopsied in these patients.