Acute myeloblastic leukaemia in sarcoidosis treated with methotrexate.

A 60-year-old man with sarcoidosis of skin and knee joints was treated with prednisone and methotrexate (MTX). A total of 590 mg MTX was given over two periods each of 3 months duration. 4 1/2 years after the first MTX dose he developed acute myeloid leukaemia. Only one more case of acture myeloid leukaemia following MTX treatment for a benign disease has been described, and until further cases have been reported the correlation might be considered a matter of simple coincidence.