Multiple myeloma after phenytoin therapy.

We report a case of multiple myeloma in a 48-year-old woman treated with phenytoin for 55 months. This association may be fortuitous. The depressive effect of phenytoin on the immune responses, however, could account for the occurrence of the dysglobulinaemia. This case points out the need for periodic examination of serum proteins in patients chronically treated with hydantoin derivatives.