An Update on Cutaneous Metastases of Internal Malignancies

Skin metastases represent a rare finding in dermatological practice, but their presence signifies an advanced disease and usually portends a poor prognosis. They commonly arise as multiple painless nodules in patients with a cancer history. Differential diagnoses are challenging, and zosteriform metastases should not be mistaken for herpes zoster. Dermoscopy typically reveals a white, structureless pattern. A skin biopsy with routine hematoxylin-eosin staining is essential for an accurate diagnosis, while immunohistochemistry is particularly useful in cases of anaplastic tumors. Breast cancer is the most common cause of skin metastasis in women, and lung cancer is the most common in men. The life expectancy after diagnosis is generally low. Cutaneous metastasectomy, electrochemotherapy, and radiotherapy are generally regarded as beneficial for palliative purposes. Intralesional cryosurgery was found to be beneficial in a few case series. Systemic immunotherapy can induce the regression of cutaneous metastases in selected patients.