Glomus tumor in a dog.

A mass of glomus tumor was found on the skin of the right foreleg of a ten-year old male mongrel dog. Histologically the mass contained some vasculatures and sheet-like proliferation of epithelioid tumor cells. Some blood vessels were rimmed by the tumor cells, which had a round to ovoid nucleus and plump eosinophilic cytoplasm. Immunohistochemically, smooth muscle actin and vimentin were demonstrated in the tumor cells. By electron microscopic examination, actin-like filaments with dense bodies were observed in the cytoplasm of the tumor cells. This is the first case report of a canine glomus tumor.