Hard nodular lesions over the chest wall
Thirteen years after undergoing a mastectomy for breast cancer, this patient developed lesions near the scar.
Diagnosis: Cancer-en-cuirasse
A core biopsy taken from our patient’s nodular region confirmed the presence of a dermal tumor. Review of the histopathologic slide revealed cells that had invaded through the basement membrane. The invasive cells were arranged as either strands or singly placed cells. Signet ring cells and increased mitosis were also seen. The intervening stroma showed desmoplasia and lymphocytic infiltrates. All of this suggested infiltrating ductal carcinoma. Immunohistochemistry was negative for estrogen receptors (ER), progesterone receptors (PR), and HER2 (human epidermal growth factor receptor 2). A bone scan using Tc-99m MDP also showed metastatic lesions in the L5 vertebra (FIGURE 2).
Cancer-en-cuirasse (en cuirasse is French for “in armor”) is a form of cutaneous metastasis that most commonly arises from breast carcinoma (69%). It can also arise from colon carcinoma (9%), melanoma (5%), ovarian carcinoma (4%), and cervical carcinoma (2%).1
The condition is characterized by the invasion of malignant cells into the cutaneous layers of the chest wall—subsequently involving interstitial spaces and lymphatics—resulting in the formation of a tough, fibrotic lesion that’s comparable to an armor or breastplate.2
While cancer-en-cuirasse is usually a local recurrence of carcinoma in patients with a history of breast cancer after mastectomy, it can, on rare occasions, be a clue for the diagnosis of underlying primary breast carcinoma.3
Cancer-en-cuirasse can be mistaken for lymphoma-en-cuirasse or angiosarcoma; a core biopsy is the definitive test to make a diagnosis.
