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Merkel Cell Carcinoma
(Neuroendocrine Skin Carcinoma; Primary Small Cell Skin Carcinoma; Trabecular Cell Carcinoma; APUDoma of the Skin; Anaplastic Skin Cancer)
Merkel cell carcinoma is a rare, aggressive skin cancer that tends to affect older white people.
Mean age at diagnosis is about 75. Merkel call carcinoma also affects younger patients who are immunosuppressed. Other risk factors include cumulative exposure to ultraviolet light, exposure to the Merkel cell polyomavirus, and having another cancer (eg, multiple myeloma, chronic lymphocytic leukemia, melanoma). Lymphatic spread is common.
Skin lesions are typically firm, shiny, flesh-colored or bluish-red, and nodular. Their most characteristic clinical findings are rapid growth and absence of pain and tenderness. Although Merkel cell carcinoma can affect any part of the skin, it is most common on sun-exposed areas (eg, face, upper extremities).
Diagnosis is by biopsy. Most patients have metastatic disease at presentation, and the prognosis is poor. Treatment is determined by cancer staging and typically includes wide local excision, often followed by radiation therapy, lymph node dissection, or both. Chemotherapy may be indicated for metastatic or recurrent cancer.
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