Histopathological and immunohistochemical characterization of mesenchymal neoplasms of the genitalia in 43 bitches

The biopsies archives from SPV-UFRGS (2000-2010) were retrieved, and cases of mesenchymal neoplasms of genitalia (uterus, cervix, vagina, and vulva) of 43 bitches were revised. Also Masson's trichrome staining (MT) and immunohistochemical characterization were evaluated. The main breeds affected were Cocker, Poodle and German Shepherd, but the greatest number of cases were observed in mixed breed dogs. The average age of the bitches was 10.6 years (3-10 years of age). The anatomical locations of the neoplasms were vagina (44.2%), uterus (27.9%), vulva (23.3%) and cervix (4.6%). Histologically, 46.5% were classified as leiomyoma, 41.9% as fibroleiomyoma, 7.0% as fibroma, and 4.6% as leiomyosarcoma. In MT staining, the fibroma had all neoplastic cells stained blue (collagen), the leiomyomas and leiomyosarcomas had less than 50% of collagen among the muscle neoplastic cells, and the fibroleiomyomas had more than 50% of collagen. Positive immunostaining for vimentin and absence for desmin was observed in fibroma. Leiomyomas were positive for vimentin in more than 50% of the cells, and for desmin (in 75% of the cases in more than 50% of the cells, and in 25% less than 50%). Regarding leiomyossarcomas, one case had immunostaining for vimentin and absence for desmin, and the opposite occurred in the other. Fibroleiomyomas were positive for vimentin in 94.4% (in more than 50% of the cells) and for desmin in 77.8% (64.3% in less than 50% of the cells, and 35.7% in more than 50% of the cells).

Neoplasias; mesenchymal neoplasms; genital system; immunohistochemistry; dogs