Breast cancer may have several cutaneous presentations, either from direct spread of tumor cells from an underlying carcinoma (primary involvement) or as a distant skin metastasis.

Inflammatory breast cancer (IBC) represents primary involvement of the skin by an underlying continuous breast cancer. IBC is a rare but aggressive form of breast cancer that tends to occur in younger women. Tumor cells block lymphatic vessels resulting in a breast that appears swollen and erythematous. A diagnosis of IBC is contingent upon meeting all the following criteria: rapid onset of breast erythema, edema and/or peau d'orange, and/or warm breast, with or without an underlying palpable mass; duration of history of no more than 6 months; erythema occupying at least one-third of the breast; and pathologic confirmation of invasive carcinoma. It may be slightly more common in Black women.

Paget disease (PD) is another example of primary involvement of the skin due to an underlying breast cancer. It is widely accepted that PD is nearly always associated with underlying breast carcinoma. Malignant cells from the underlying ductal adenocarcinoma invade the nipple unit and overlying periareolar skin. The malignant cells spread through the normal epidermis in "pagetoid fashion," admixed among normal keratinocytes.

Breast carcinoma has been identified as the most common tumor presenting with cutaneous manifestations in women. Cutaneous metastasis can serve as the first presenting sign of breast cancer, and it usually occurs later in the disease course. A wide range of morphologies has been identified. The most common is nodular metastatic carcinoma, which presents as one or more non-tender, firm papules or nodules that may be skin-colored, pink, red, violaceous, or brown.

Other rarer presentations include:

• Telangiectatic metastatic carcinoma – Caused by invasion of superficial lymphatic vessels and often presents with pruritus.
• Carcinoma erysipeloides – A rare form of cutaneous metastasis that presents as an erythematous patch or plaque that resembles erysipelas or cellulitis. It is caused by the occlusion of superficial lymphatics by metastatic tumor cells, and edema may be present. Most cases of carcinoma erysipeloides are due to underlying breast adenocarcinoma, although it has been associated with tumors of the pancreas, stomach, lung, rectum, ovary, and parotid glands. It is rarely the first sign of malignancy and usually appears after treatment with radiation, chemotherapy, or surgery. The appearance of carcinoma erysipeloides portends a poor prognosis.
• Carcinoma en cuirasse (sclerodermoid carcinoma) – Occurs after initial treatment. It is an aggressive form of cutaneous metastasis that appears as firm, indurated, and sclerotic plaques of the skin of the chest wall and sometimes the upper abdomen.
• Alopecia neoplastica – Scarring alopecia due to metastasis to the scalp. Neoplastic cells are thought to destroy hair follicles via induction of inflammation and fibroplasia. Breast cancer is the underlying malignancy in 85% of these patients.

Other rarer forms of cutaneous manifestations of breast carcinoma that have been described in literature include subungual metastases, zosteriform metastases, malignant-melanoma-like metastases, metastases to eyelids, granuloma pyogenic-like metastases, and dermatomyositis.

Related topics: female breast cancer, male breast cancer