After decalcification, the specimen showed a partially ulcerated and slightly parakeratotic epithelium. In central areas, an extensive proliferation of neoplastic cells with sparse eosinophilic cytoplasm, extreme polymorphic nuclei, and a high mitotic index were noted near the epitheliostromal junction, infiltrating the submucosa. Some of the cells had a spindle cell–like or polygonal appearance. The depth of invasion was 0.3 mm. Immunohistochemical investigations showed strong S100 protein expression of the tumor cells but were negative for HMB-45. The neoplastic cells did not invade the cancellous bone of the hard palate, but there was an extensive mixed chronic inflammatory cell infiltrate around the tumor. The final diagnosis was invasive amelanotic melanoma classified as a pT2, pN0, pM0 tumor.
Missing Article Title. Arch Dermatol. 2002;138(12):1607. doi:10.1001/archderm.138.12.1607