Canine oral cavity T-cell lymphoma – histopathological and immunohistochemical study

Abstract

This study presents a case of an unusually located canine T-cell lymphoma. A 5-year-old female dachshund was presented with a tumour located in the buccal mucosa. The tumour was excised, fixed, processed routinely for histopathology and stained. Microscopically, a dense infiltration of round cells with scant cytoplasm, large nuclei and numerous mitotic figures was detected within the mucosa. The tumour was diagnosed as a roundcell tumour. Subsequently, additional tumours developed in the mandibular and hock joint areas. The primary tumour was stained immunohistochemically using an antibody panel (CD3, MHCII, mast cell tryptase, CD18, CD79a). The tumour cells showed variable cytoplasmic expression of CD3, moderate-to-strong cytoplasmic or membranous expression of MHCII, and they were mast cell tryptase, CD18 and CD79a negative. The final diagnosis was T-cell lymphoma. The dog passed away within the next two months. This study revealed, that immunohistochemistry is necessary to diagnose canine oral cavity round cell tumours....