We report an unusual case of non-Hodgkin T cell lymphoma associated with sarcoidosis. A 44-year-old woman was histologically diagnosed as having sarcoidosis in 1966. Diffuse interstitial lung disease and erythematous skin nodules disappeared following steroid therapy. Twenty years after sarcoidosis onset erythematous nodosum recurred and biopsy specimens revealed non caseating epithelioid granuloma. Thirty-seven months later a malignant T cell lymphoma developed in the skin portion where sarcoid lesions recurred. We discuss the possible relationship between the sarcoid inflammatory process and the development of a malignant T cell clone as origin of the T cell lymphoma.