Skin metastases are rare in the routine clinical practice of dermatology, but are of major clinical significance because they usually indicate advanced disease. We reviewed the literature on skin metastasis regarding recent trends in clinical presentation and diagnosis of the most common cutaneous lesions. An extensive literature review was conducted using PubMed from May 26, 2011 to July 16, 2013 relating cutaneous metastases. Articles chosen for reference were queried with the following prompts: “Cutaneous metastases”, “clinical presentation”, “histological features”, and “immunohistochemistry”. Further searches included “treatment” and “management” options for “metastatic breast”, “metastatic colorectal”, “metastatic melanoma”, “metastatic lung”, and “hematologic cancers.” We also reviewed the literature on the current management of melanoma as a model for all cutaneous metastatic disease. Our own clinical findings are presented and compared to the literature. Additionally, we highlight the most useful immunohistochemical studies that aid in diagnoses. Several novel therapies and combination therapies such as electrochemotherapy, vemurafenib, and imiquimod will be discussed for palliative treatment of cancers that have been found to improve cutaneous lesions. We review these notable findings and developments regarding skin metastases for the general dermatologist.

This is the largest review of skin metastases in the United States in the past 25 years. We found the primary cancers that metastasize to the skin have changed in frequency from previous studies. Our data are helpful in indicating which cancers have the strongest predilection for skin metastasis. Identification of these cancers can help both the clinician and patient detect early signs of metastases, which may allow for earlier diagnosis, implementation of therapy, and possible prolonged survival.

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A 65-year-old man presented with a history of a giant blue plaque of the parietal scalp since childhood. Biopsy revealed a cellular blue nevus. The blue nevus was observed for 10 years and thought to be unchanged until a new adjacent lesion was noted. Biopsy of the new lesion revealed metastatic malignant melanoma. A wide excision was performed of the original lesion which revealed malignant melanoma arising in a blue nevus. Areas within the blue nevus were consistent with a pilar neurocristic hamartoma, whereas other areas were consistent with a common blue nevus. Subsequent satellite metastases developed, with early metastases resembling blue nevi except for the absence of a stromal component and the presence of hyperchromatic nuclei. Later metastases were typical of metastatic melanoma. This case illustrates the uncommon evolution of malignant melanoma from a blue nevus. The histological features and relationship between melanoma, blue nevus, and pilar neurocristic hamartoma are reviewed.

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