[A Case of Stage Ⅳ Triple Negative Breast Cancer(TNBC)in Which S-1 Was Successful against Armor-Like Infiltration of the Chest Wall].

A 51-year-old female patient visited our department with a complaint of pain in the left breast. She was found to have Stage Ⅳ breast cancer with liver metastasis. The biopsy-based historical diagnosis was triple negative breast cancer(TNBC).