Increasing numbers of patients are being treated with TNF-alpha inhibitors. Two patients in our outpatient clinic developed Merkel cell carcinoma during treatment with TNF alpha inhibitors. Since this is a very rare malignancy, this is a remarkable observation.
A 70-year-old male with rheumatoid arthritis had been treated with etanercept for two years when he discovered a nodule on his elbow that started growing rapidly. It was diagnosed as Merkel cell carcinoma. Despite treatment, the patient died 2 years later.
Merkel cell carcinoma is an aggressive malignancy with a clinically benign aspect. Patients treated with TNF-alpha inhibitors possibly have an increased risk of developing this malignancy.