Fibroepithelial polyps of the vagina in bitches: a histological and immunohistochemical study.

The histological and immunohistochemical features of 13 cases of suspected vaginal fibroepithelial polyps are reported. The characteristic microscopical features of these lesions were an abundant oedematous or fibrous stroma containing spindle-shaped and stellate cells and the presence of variable inflammation and haemorrhage. There was often a superficial layer of compressed tissue, but the stroma in the peripheral areas of the masses was generally more loosely arranged than in central areas. The connective tissue cells expressed vimentin and desmin, but did not express smooth muscle actin or calponin. Individual cases had additional changes including granulomatous inflammation, epithelial dysplasia suggestive of papillomavirus infection and a lesion resembling phyllodes tumour in women.