Carcinoma en cuirasse (CEC) is a rare, aggressive form of cutaneous cancer metastasis. It usually represents a tumor recurrence but occasionally can be the initial presenting sign of a primary malignancy. The most common cancer to present as CEC is breast cancer; CEC has also been rarely seen in the setting of primary lung cancer, gastrointestinal cancers, and genitourinary malignancies.

CEC presents as thickened, indurated, sclerodermatous plaques on the chest wall, akin to a hardened breastplate of armor ("en cuirasse" is French for "in armor"). It is characterized initially by smaller papules and nodules that coalesce to form larger plaques. CEC can progress to restrict movement of the chest wall and impede respiration. Pathogenetically, lymphatic destruction by cancer cells is thought to contribute to localized lymphedema and these lipodermatosclerosis-like changes.

These skin findings may be associated with pruritus and/or pain.