Imatinib-induced hyperpigmentation of the hard palate in a Japanese patient with chronic myeloid leukemia: A case report

Imatinib mesylate is currently considered the first-line treatment for chronic myeloid leukemia (CML) and gastrointestinal stromal tumor (GIST). This drug is associated with oral mucosa hyperpigmentation. A 63-year -old Japanese man was presented with a diffuse blue-gray pigmentation on the hard palate. The patient had been treated with imatinib for CML for over five years until then. Histopathological examination revealed melanin deposits in the lamina propria of hard palate mucosa. Based on the medical history and clinical and histological findings, the palatal lesion was diagnosed as imatinib-induced hyperpigmentation. Periodic follow-up confirmed that the palate lesion persisted without any clinical changes.