Pleomorphic Appearance of Breast Cancer Cutaneous Metastases.

Cutaneous metastases occur in approximately 10% of oncology patients as a feature of a persistent solid tumor or the harbinger of recurrent neoplastic disease. However, they can be the presenting manifestation of an unsuspected visceral malignancy in one percent of previously cancer-free individuals. Metastatic skin lesions from breast carcinoma are diverse in their appearance. The clinical presentation of cutaneous metastases in three women with breast cancer is described and both the morphology of skin metastases caused by breast carcinoma and the conditions that are mimicked by breast cancer cutaneous metastases are reviewed. Skin metastases from breast carcinoma commonly appear as firm, flesh-colored to red, smooth or ulcerated or crusted, nodules, papules, and plaques on the ipsilateral chest wall and breast. However, unique sites of breast cancer cutaneous metastases are the eyelids, inframammary folds, ipsilateral lymphedematous arm, scalp, subungual nail bed, and umbilicus; in addition, skin metastases can occur in mastectomy scars and radiation therapy ports. Carcinoma erysipelatoides, carcinoma telangiectoides, and carcinoma en cuirasse are classic patterns of skin metastases that can be observed in breast cancer patients; carcinoma hemorrhagiectoides is a recently observed skin metastases pattern that has also been noted in oncology patients with breast carcinoma. The pleomorphic skin lesions of breast cancer metastases can masquerade as benign cutaneous lesions and tumors (such as a collision tumor, cyst, dermatofibroma, and milia-en-plaque), cutaneous malignancies (such as melanoma and non-melanoma skin cancers), infections (such as cellulitis, folliculitis, herpes zoster, and paronychia), reactive erythema (such as erythema annulare centrifugum, and urticaria), skin conditions (such as alopecia areata, dermatitis, hidradenitis suppurativa, and scleroderma), and vascular lesions (such as angiokeratoma, angiosarcoma, lymphangioma circumscriptum, purpura, and pyogenic granuloma). In addition, breast carcinoma cutaneous metastases can not only mimic other miscellaneous conditions such as erosions and ulcers, Paget's disease, and papillomatosis cutis lymphostatica but also have unusual morphology such as targetoid lesions or a sharply demarcated red infiltration of the nasal tip similar to a clown's nose. The possibility of a breast cancer cutaneous metastasis should be considered in the evaluation of a patient with breast cancer--and although less likely, in a cancer-free individual--who develops a new and/or a treatment-unresponsive cutaneous lesion. A biopsy of the skin lesion is necessary to confirm the diagnosis of breast cancer cutaneous metastasis.