Imatinib induced melasma-like pigmentation: Report of five cases and review of literature.

Imatinib mesylate is a cytotoxic agent that targets tyrosine kinase. Common side effects of this drug include nausea, edema and maculopapular rash. Hypopigmentation is a commonly reported side effect of this drug while hyperpigmentation has rarely been described. We describe five cases of melasma-like pigmentation induced by this anti-cancer drug. Four of the patients were diagnosed with gastrointestinal stromal tumor while one had chronic myeloid leukemia. Patients received imatinib mesylate in a dose of 400 mg daily. Over an average period of 3 months, well defined hyperpigmented macules appeared over the convexities of the face. One of the patients also developed similar pigmentation on the forearm. Other causes of hyperpigmentation were excluded in each patient.