Subapriya, SPazhanivel, NRamesh, STANUVAS2021-12-162021-12-162021https://krishikosh.egranth.ac.in/handle/1/5810179365TNV_PIJ_2021_10(5)1389-1392A 12 year old, male, Spitz breed dog was presented with a mass in the thigh region for tumour diagnosis. Samples were collected by Fine Needle Aspiration Biopsy (FNAB) for cytological examination. Tissue samples were collected post surgical excision for histopathological, immunohistochemical and ultrastructural investigation. Cytology of the mass revealed pleomorphic neoplastic cells containing round to oval nuclei and prominent multiple nucleoli. Histopathological examination revealed varying sized ducts and tubules containing pleomorphic neoplastic cells containing round to oval vesicular nuclei, prominent nucleoli and pale eosinophilic cytoplasm. Transmission Electron Microscopy (TEM) revealed tumour cells with features of anisokaryosis, multiple nuclei in a cell, margination of heterochromatin and prominent nucleoli with coarse chromatin. Based on the above findings the mass was diagnosed as sweat gland adenocarcinoma.EnglishVeterinary ScienceArticle