• Journal of Veterinary Clinics
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• v.26 no.6
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• pp.612-615
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• 2009

A 10-year-old intact male mixed breed dog was presented with a three-month history of massive oral mass. Physical examination revealed extending mass from the right upper gingiva. No metastasis was found at the time of presentation. Histopathologic examination of biopsied tissue from the oral mass was consistent with a neuroendocrine tumor with generalized epithelioid cells and few spindle cells. There were highly mitoses and no visible melanin granules with H&E staining. Immunohistochemical staining for Melan A was performed on section of tumor and was strongly positive. Diagnosis was made as amelanotic malignant melanoma based on histopathology with Melan A immunohistochemistry. This case study indicates that the Melan A immunohistochemical staining may be valuable to diagnose amelanotic malignant melanoma in dogs.