Background: Primary bone tumours are uncommon and poorly reported in cats but osteosarcoma (OSA) is the most frequent, mostly in elderly animals. Giant cell-rich OSA is considered rare in the literature representing 3% of all OSA in humans. The mitotic index seems to have a significant effect on the survival time of cats affected by this neoplasm as well as the tumour histopathological grade. The objective of this study was to report the cytological and histopathological findings of a giant cell rich OSA in a 4-year old cat with persistent feline leukemia virus (FeLV) antigenaemia.Case: A 4-year-old male neutered cat was referred with a history of persistent FeLV viraemia and pelvic limb lameness with a firm swelling. Previous radiographs of the affected limb revealed bone lysis in the third and fourth metatarsals and increased soft tissue radiopacity in the tarsal region. The referral veterinary assumed it to be osteomyelitis and initiated clinical treatment with antibiotic and anti-inflammatory. The cat was referred after there was no response to medical treatment. The cat was presented with a 5cm diameter ulcerated mass, with putrid odor in the pelvic limb. Complementary exams were performed, and abnormalities were found, including increased urea, creatinine, calcium and potassium, and decreased sodium and phosphorus. A new radiograph showed exuberant bone proliferation, with increased radiopacity involving tarsal, metatarsal, distal third of tarsal I and II, and distal diaphysis of metatarsal V, without compromising the metaphyseal region of distal diaphysis of metatarsal IV. Chest radiographs and abdominal ultrasound were unremarkable. Fine-needle aspiration was performed for cytological analysis, which reavealed a moderate amount of pleomorphic mesenchymal cells with moderate adhesion, cytoplasm with a format ranging from fusiform to stellate, pronounced anisocytosis and cellular pleomorphism, and elevated nucleus:cytoplasm ratio. Nucleus was oval and presented loose chromatin, single to double large and evident nucleolus, frequent karyomegaly, along with marked anisocariosis and nuclear pleomorphism. Multinucleated giant cells were and there was a single mitotic figure in 12 high power fields (0.196 mm2 FN20/400x). Therefore, it was suggestive of malignant mesenchymal neoplasia with possibility of OSA, fibrosarcoma oe undifferentiated sarcoma. Limb amputation with femoral disarticulation was performed uneventfully. The material was conserved in 10% formalin, submitted to macroscopic and microscopic evaluation, which showed a large number of fusiform and stellate cells, with indistinct edges, scarce eosinophilic cytoplasm, high nucleus:cytoplasm ratio and oval nucleus, presenting moderate to marked anisocariosis, loose chromatin, with unique and evident nucleoli, besides of bone trabeculae. Nuclear pleomorphism was moderate and there was four mitotic figures in three random high-power fields (400x). It was observed areas of vascular ectasia, and neoplastic embolization in lymphatic and blood vessels. Among the cells, collagenous stroma was predominant but in some areas there was an eosinophilic amorphous material with the possibility of osteoid matrix or collagen. There was also a large numbers of multinucleated giant cells. The histopathological result was compatible with a grade III giant cell rich OSA.Discussion: Although bone tumours are uncommon in cats, OSA is the most frequent, affecting maingly middle-aged to elderly cats, with a mean age of 10 years, which is different from the present report in a 4-year old cat, with FeLV persistent viraemia. Retroviral status may have influenced the development of the disease at na early onset. FeLV induces uncontrolled cell proliferation through insertional mutagenesis (usually near myc) inducing malignant neoplasias, mainly lymphoma, but also multiple cartilaginous exostosis, which, along with osteomyelitis and bone cyst were included in this patient´s list of differential diagnoses. Despite the macroscopic and radiographical andagressiveness there was no metastasis identified through chest radiographs or abdominal ultrasound, and feline OSA is associated with a lower metastatic rate, if compared to canine OSA. Cytological analysis was compatible with malignant mesenchymal neoplasia, being suggestive of giant cell rich OSA. There is no cytological classification for OSA, however cytological findings of malignancy may be correlated with the patient's clinical course. Cytological features were in agreement with the histopathological findings, compatible with a grade III giant cell rich OSA. Therefore, it is concluded that the characteristics of malignancy presented by cytology were sufficient for the recommendation of amputation of the affected limb, once there was no imaging sign of metastases in the chest or abdomen.

Background: Sporotrichosis is a dermatozoonosis that affects mammals in general, with the domestic feline (Felis catus) being the most epidemiologically important species. However, diagnosis of this disease in dogs is important considering the proximity with people and with other communicants. The epidemiology of sporotrichosis is already known in some states of Brazil, especially in the southeast region, but to the best of our knowledge there are no reports of sporotrichosis in non-human species in the state of Espírito Santo. This paper aimed at describing the first case of canine sporotrichosis in Espírito Santo, Brazil.Case: A 10 year-old Bull Terrier male dog was presented with nodular non-ulcerated lesions on the head and nodular ulcerated lesion on the nasal planum. The dog had a previous diagnosis of a low-grade mast cell tumour and palpebral melanoma. Mast cell tumour was treated with scrotum ablation (and orchiectomy) and bilateral inguinal lymph node removal, followed by chemotherapy with twelve intravenous infusion of vinblastine, along with prednisolone. Cutaneous lesions in the head and nasal planum appeared two months after finishing chemotherapy. At further anamnesis, the pet´s responsible reported that the dog had the habit of hunting cats that entered the residence, which raised the hypothesis of sporotrichosis. An undiagnostic cytology was performed, followed by a fungal culture, positive for Sporothrix schenckii. Treatment was then initiated with itraconazol (Oficial generic drug), at a dose of 10mg/kg/SID, until clinical remission, obtained after 60 days, maintaining it for 60 more days. Patient showed completed recovery, with no further complatints after a follow-up of more than 220 days.Discussion: Sporotrichosis is considered a rare disease in dogs, with isolated cases in the literature. The dog of the present report was diagnosed with sporotrichosis two months after the end of a chemotherapy treatment for a mast cell tumour. Therefore, it is suggested that the patient in this study was infected during an immunosuppressive phase. The same can occur with other immunosuppressive treatments, such as glucocorticoid, also included in the chemotherapy treatment of this patient, calcineurin inhibitors (cyclosporine) and mercaptopurine derivatives (azathioprine). Cytology is usually unconclusive for such lesions in dogs, once only a few yeast might be present. Nevertheless, the definitive diagnosis was obtained through fungal microculture. Treatment with itraconazol was successful but dogs might also present favorable responses to ioidine. Itraconazole is a fungistatic drug, fungicidal only in high doses. For this reason, if the fungistatic dose is not administered for sufficient time, recurrences may occur. In the last three years, Espirito Santo has become a new epidemiological scenario for sporotrichosis, and it is placed in the route of transmission, closely to Rio de Janeiro. Cats are the most affected animals and are commonly responsible for transmission to other species, including humans. The increase in cases of canine sporotrichosis requires its inclusion in the differential diagnosis of nodular-ulcerative lesions, along with cutaneous neoplasias and immune-mediated diseases.