Diphenylhydantoin and insulinoma

Editor, I read the recent publication on the use of diphenylhydantoin for treatment of insulinoma by Nabbout et al. with great interest [1]. Nabbout et al. concluded as follows: “We believe that DPH is a potent inhibitor of insulin secretion and, thus, is suitable as a temporary therapeutic measure in the preoperative period of patients with insulinoma, as well as an alternative to surgery for those who are not surgical candidates [1].” There are some sporadic reports on the success of using diphenylhydantoin [2], [3]. However, there is a need for more evidence to reach this statement. Success in a few cases might not warrant the efficacy of this new therapeutic approach for insulinoma.