Atypical carcinoid tumor of the thymus with ectopic ACTH production developed during the course of etanercept treatment--case report.

Ever since the introduction of anti-tumor necrosis factor (TNF) agents, concerns have been raised regarding their potential for developing malignancy. We report the development of thymic atypical carcinoid tumor 9 months after the initiation of etanercept therapy in a patient having refractory spondylarthritis. This case indicates the need for following large cohorts of patients receiving anti-TNF agents to address the long-term effect of these agents on malignancies.