Treatment of Primary and Metastatic Multifocal Mucosal Melanoma of the Oral Cavity with Imatinib

BACKGROUND: Mucosal melanoma of the oral cavity is a rare entity and accounts for less than 1–3% of all melanomas. Contrary to cutaneous melanoma, primary oral melanoma more commonly harbors mutations in c-KIT. METHODS: A 64-year-old man presented with asymptomatic, multiple, brown-to-black macules in the oral cavity. A biopsy was taken and histopathology exhibited mucosal melanoma. In molecular analysis, a c-KIT mutation was proven and a CT scan revealed pulmonary metastases. Due to the multifocality of the lesions, the metastases, and the mutation status, a therapy with imatinib was initiated. RESULTS: After 1 year of therapy, progressive disease in the lung was noticed. Therefore, the therapy was switched to a PD-1 antagonist and a CTL-4 antibody. CONCLUSIONS: Our case suggests that imatinib may be considered as first-line treatment for both locally advanced and distant primary multifocal oral melanoma, for which surgery or radiotherapy of the primary tumor is impossible.