Metastatic Invasive Lobular Carcinoma to Multiple Gastric Fundic Gland Polyps: A Rare Pattern of Gastric Involvement

Breast cancer is one of the most common causes of cancer-related deaths among women. Here, we report the case of a 62-year old female with a history of invasive lobular carcinoma (ILC) of the breast, initially treated with neoadjuvant chemotherapy and mastectomy, who presented five years later with anemia. Endoscopic evaluation revealed over 50 gastric fundic gland polyps, with 8/10 sampled polyps showing metastatic involvement with ILC. Genetic testing showed no mutations in the CTNNB1 or APC genes. This case raises the question of whether fundic gland polyps provide a unique microenvironment favorable for metastatic seeding. It also illustrates the importance of maintaining a high index of suspicion for disease recurrence or metastasis in the differential diagnosis of gastric findings, even years after the initial diagnosis and treatment of ILC.