Imatinib mesylate–induced repigmentation of vitiligo lesions in a patient with recurrent gastrointestinal stromal tumors

We report a case of vitiligo with localized repigmentation induced by imatinib mesylate. An elderly Chinese man has been characterized with recurrent gastrointestinal stromal tumors originated from interstitial cells of Cajal with gain-of-function c-kit mutation. His recurrent tumors have responded to imatinib mesylate therapy. To our surprise, his decade-long vitiligo was dramatically ameliorated by localized repigmentation, which is considered to be the side effect of imatinib mesylate. Hypopigmentation induced by imatinib mesylate with possible molecular blockage to a melanin-dependent KIT signal has been well documented; however, our case with repigmentation suggested that KIT signal of melanin formation would be much more sophisticated than we have believed.