A case of desmoplastic melanoma of the maxillary gingiva

Abstract

Desmoplastic melanoma (DM) is a subtype of malignant melanoma, and there are very few reports on the occurrence of this disease in the oral region. Since DM is mainly composed of achromatic spindleshaped tumor cells, its clinical and histopathological diagnoses are difficult. However, immunohistochemical staining is useful for the diagnosis of DM. We herein present a case of DM in the maxillary gingiva of a 69-year-old woman. Swelling had been observed in the gingiva surrounding the upper left six tooth of this patient since 2018, and in 2020 a rapid increase in the swelling was observed. Thus, the patient consulted a nearby dental clinic and underwent resection due to a clinical diagnosis of epulis. Histopathologically, the patient was diagnosed with sarcoma and referred to our department for detailed examination and treatment. We suspected a sarcomatous malignant tumor and performed a partial left upper jaw resection. Histopathological findings revealed that the spindleshaped cells were arranged in an intricate manner. Immunohistochemical staining was positive for S-100 protein, SOX10 and MelanA, and DM was diagnosed.