Breast carcinoma en cuirasse (CeC) is an extremely rare form of cutaneous 
metastases of breast cancer, characterized by diffuse sclerodermoid induration 
of the skin. It may be difficult to distinguish CeC from some skin diseases, 
including postirradiation morphea, inflammatory breast cancer, radiation 
dermatitis, and other cutaneous metastases, but it can be easily discerned by 
histology. Because of the small number of documented cases, the treatment 
consensus has not been clearly defined. Here, we show a 45-year-old woman with 
grade III infiltrating ductal carcinoma manifesting as CeC to the chest wall. 
Early diagnosis and treatment are essential to prevent the catastrophic natural 
progression of this rare malignancy.