Merkel-Cell Carcinomas in Patients Treated with Methoxsalen and Ultraviolet A Radiation

Abstract

Merkel-cell carcinoma is a very rare small-cell carcinoma of the skin.¹ Probably derived from Merkel cells, the mechanoreceptors located in the basal layer of the epidermis, these tumors are asymptomatic, solitary, small red-purple subcutaneous nodules.² Most are found in elderly persons at sites exposed to the sun. The two-year survival rate is about 50 percent.³ As is the case for non-melanoma skin cancers, especially squamous-cell cancers, exposure to ultraviolet radiation and, possibly, ionizing radiation are risk factors for Merkel-cell carcinoma.