PMC4868936_01
Clinical aspect of OMM. a Ulcerated nodule and irregular macules on the hard palate extending to the soft palate. b Nodule located on the gingiva and alveolar mucosa (upper left lateral incisor region). The color of the lesions varied from dark blue to black.
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F1
Intraoral examination showed multiple lesions represented by macules and nodules on the hard and soft palate, superior alveolar mucosa and gingiva (fig. 1a, b).
Histological examination. a Sheets and nests of atypical melanocytes located in the corium. HE. Final magnification x100. The overlying epithelium was atrophic and not pigmented. b Atypical melanocytes arranged in an alveolar pattern, some present round nuclei of various sizes, occupying nearly the entire cell cytoplasm and prominent nucleoli. A few tumor cells contain dense cytoplasmic melanin pigment (arrow). HE. Final magnification x400.
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F2
Histological examination (fig. 2a, b) showed sheets and nests of melanocytes, some with round, plasmacytoid or epithelioid morphology in the superficial corium extending to the deep tissues.
Immunohistochemical analysis. Neoplastic melanocytes positive for HMB-45 (a), melan-A (b), S-100 (c; final magnification x400) and Ki-67 (d), which shows a labeling index of around 25%. a, b, d Final magnification x100.
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F3
Immunohistochemistry showed tumor cells positive for HMB-45 (fig. 3a), melan-A (fig. 3b), S-100 (fig. 3c), Ki-67 (fig. 3d) and negative for AE1/AE3 (not shown), confirming the diagnosis of melanoma.