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. Immunohistochemical
ly, smooth muscle actin and vimentin were demonstrated in the tumor ce
lls. By electron microscopic examination, actin-like filaments with de
nse bodies were observed in the cytoplasm of the tumor cells. This is
the first case report of a canine glomus tumor.