Merkel cell carcinoma. Long term survival in a patient with proven brain metastasis and presumed choroid metastasis.

Merkel cell carcinoma (Trabecular carcinoma) is a rare malignant tumor of the skin. Because these tumors tend to spread locally via the lymphatic system, very few papers have dealt with the treatment of distant metastasis. Systemic disease is uncommon and usually fatal. In this paper, we report a case of Merkel cell carcinoma with proven brain metastasis and a solid choroidal tumor. The patient responded well to radiation and chemotherapy and is alive and neurologically intact three years after diagnosis. All previous patients with metastatic Merkel cell carcinoma to the brain died within two months of the diagnosis. We use this case to discuss possible routes of metastatic dissemination and to review the treatment options in patients with distant metastatic disease. To our knowledge, this is the first reported case of presumed choroidal metastasis of Merkel cell carcinoma and the longest documented survival in a patient with brain involvement.