Metastatic Pattern Of Invasive Lobular Carcinoma Of The Breast-Emphasis On Gastric Metastases

Background and Objectives: Breast invasive ductal carcinoma (IDC) and invasive lobular carcinoma (ILC) have different metastatic patterns, but the exact pattern of metastases from ILC is poorly known. This study aimed to determine the frequency of ILC metastases in atypical locations, with an emphasis on gastric metastases.Methods: Patients with ILC treated at the Saint-Sacrement Hospital (Quebec City, Canada) and the Maisonneuve-Rosemont Hospital (Montreal, Canada) between January 2003 and December 2009 were retrospectively reviewed. Demographic, clinical, and follow-up data were retrieved from the medical charts. Metastases that were diagnosed during follow-up were recorded.Results: Among the 481 patients with ILC, 74 (15.4%) were diagnosed with metastases after a median follow-up of 46 months. Among these 74 patients, 41.9% had metastases in atypical sites. Five patients were diagnosed with histologically confirmed gastric metastases of ILC.Conclusion: Metastases of breast ILC to atypical sites might be more frequent than previously reported. Clinicians should keep a high level of suspicion when a patient with a history of ILC develops digestive symptoms. It is important to differentiate metastases from a primary GI tumor by using immunohistochemical markers. (C) 2016 Wiley Periodicals, Inc.