Immunohistochemical expression of vimentin, E-cadherin, and CD45 in natural cases of canine cutaneous round tumors.

Round cell tumors are common cutaneous lesions in dogs, with increased occurrence percentages among different skin tumors. This study aimed to investigate the frequency as well as gross and pathological characteristics of round cell tumors in natural cases of tumorous dogs in relation to breed, sex, and age. Moreover, it aimed to evaluate the immunohistochemical expression of a panel of immunohistochemical stains, including vimentin, E-cadherin, and cluster of differentiation (CD45) as an adjunct technique for the differential diagnosis of cutaneous round cell neoplasm. Data were collected from 64 dogs of both sexes (36 females and 28 males), various breeds, and different ages (8 months to 7 years). The histopathological nature of neoplastic growth was reported, and neoplasm prevalence was classified using age, sex, breed, and site on the body. We observed 48 cases of transmissible venereal tumors, 12 cutaneous histiocytomas, and 4 histiocytic sarcoma. Immunohistochemical characterization revealed an intense positive immunoreactivity for vimentin in transmissible venereal tumor cells and moderate positive immunoreactivity for E-cadherin and CD45 in cutaneous histiocytoma and histiocytic sarcoma cells. In conclusion, the canine transmissible venereal tumor was the most frequent form of round cell tumor; thus, a definitive cutaneous neoplasm diagnosis should be based on histopathological morphology and immunohistochemical findings.

Prevention and treatment of Encephalitozoon cuniculi infection in immunosuppressed rabbits with fenbendazole.

This study was conducted to evaluate the efficacy of oral administration of fenbendazole (20 mg/kg body weight) prior to and after experimental infection of immunosuppressed rabbits with Encephalitozoon cuniculi. A total of thirty rabbits were divided into five groups: NN (non-immunosuppressed; non-infected), IN (immunosuppressed; non-infected), IPI (immunosuppressed; protected-infected), ITI (immunosuppressed; treated-infected), and II (immunosuppressed; infected) groups. Fenbendazole was administered as a prophylactic for seven successive days before infection with E. cuniculi and as a treatment for four weeks initiated on the 28th day post-challenge (PC). Experimental rabbits were infected with intraperitoneal injection of 2 × 105E. cuniculi spores. Parameters evaluated were body weight, detection of spores in urine, serum antibody assay, hematological, biochemical and histopathological changes. The IPI and ITI groups showed a significant better final bwt than the II group. Spores were detected in urine of all infected rabbits from the 28th day PC until the end of the study. The IPI group showed the least values of antibodies (IgG) compared to the ITI and II groups. Concerning histopathological changes, the intensity of the lesions was marked particularly in the II rabbits and to a lesser extent in the ITI rabbits. Noticeable improvement was found in the IPI rabbits. It could be concluded that fenbendazole was effective to some extent in protection of rabbits against E. cuniculi infection, while when administered as a therapeutic no significant effects were observed.