Locally advanced invasive lobular carcinoma presenting as skin erythema, with multimodality imaging correlation.

Invasive lobular carcinoma comprises 10-15% of invasive carcinomas of the breast. Its inconspicuous pattern of proliferation may lead to tumor manifestations that can be challenging to detect on mammography and clinical exam, which can result in tumor detection at advanced size and stage. This case demonstrates a locally advanced invasive lobular carcinoma and its subtle growth pattern illustrated on several imaging modalities, as well as its unique initial clinical presentation of skin erythema mistaken for rash.