Solitary Osseous Plasmacytoma of a Lumbar Vertebrae with Systemic Involvement in a Dog

Background: Myeloma-related disorders are characterized by proliferation of neoplastic plasma cell or immature immunoglobulin secreting B-lymphocytes, and include multiple myeloma, M-macroglobulinemia and extra-medullary plasmacytoma (cutaneous or extra-cutaneous). Solitary osseous plasmacytoma (SOP) is considered an unique entity among extra-medullary extra-cutaneous plasmacytoma. It is an unusual neoplasia in dogs, predominantly found in middle-aged to older animals, with a higher incidence in bones of axial skeleton. Dogs with vertebral SOP present neurological signs related to spinal cord compression, but progression to multiple myeloma is related to a poor outcome. As in humans, progression to multiple myeloma occurs in most cases, although it may take months or years from its initial presentation. SOP´s biological behaviour, incidence and prognostic are rarely documented. Chemotherapy with melphalan and prednisolone represent the most used protocol for multiple myeloma. However, in SOP, the combination of chemotherapy with local approaches is controversial before the evidence of systemic disease. This paper aims at reporting a case of SOP in a lumbar vertebrae of a dog, with systemic involvement. Case: A 11-year old male mixed breed dog was attended presenting muscle weakness, lethargy, anorexia, adipsia and intense pain manifestation. The dog also presented multiple skin nodules, previously diagnosed as a plasmacytoma, through cytology. The dog´s poor clinical condition and aggressive temper, associated with suspicious of an advanced myeloma-related disorder, resulted in the decision for humanized euthanasia. At necropsy, a pale, friable and hemorrhagic mass was identified on the L3 lumbar vertebrae, associated with an osteolytic bone lesion and spinal cord compression. Histopathological analyses revealed proliferation of plasma cells, with pale perinuclear halo, moderate cellular pleomorphism, 10 binucleated cells and 10 mitotic figures per 10 high power fields, compatible with extramedullary plasmacytoma of the mature type, in the lumbar vertebrae (SOP). It was also seen myeloma-related lesions in the skin and subcutaneous, prostate, heart, superficial mandibular and axillary lymph nodesDiscussion: Solitary osseous plasmacytoma is a myeloma-related disorder rarely reported in dogs. Its biological behaviour is poorly characterized, however progression for multiple myeloma is common in humans and dogs, and it is related to a poor outcome. As the present report, systemic progression of SOP has been previously described and although an overt bone marrow infiltration was not detected, such possibility can not be excluded, once multiple myeloma distribution in the bone marrow is often multifocal. Although chemotherapy is the treatment of choice for multiple myeloma, its indication for SOP is conditioned to the evidence of systemic disease. It might delay tumour progression, but its early implementation may favor the selection of resistant neoplastic clones, making it ineffective when progression to multiple myeloma occurs. In humans radiotherapy is the treatment of choice for SOP, however it may be indicated in association to surgery. A retrospective study showed a higher survival rate in patients with SOP in the axial skeleton, which received surgical treatment combined with radiotherapy, if compared to those treated with surgery or radiotherapy alone. Decision for euthanasia was made based on the suspicious of advanced myeloma-related disorder, patient´s medical condition and aggressive temper, which limited diagnostic investigation and treatment

Focal Peripheral Neuropathy Associated with Lymphoma in Dogs

Background: Peripheral neuropathies result in sensory, motor or autonomic dysfunctions due to impairment of peripheral spinal or cranial nerves. Neoplasms such as lymphoma are cited as one of the many aetiological causes and it may affect the nerve directly, by compression, or indirectly, or paraneoplastic, by remote action of the neoplasm located in an extra-neural site. This study aimed to report two cases of cranial nerve neuropathy (trigeminal and facial) associated with canine lymphoma, contributing to a better understanding of its paraneoplastic effects on the nervous system, as well as the diagnosis and treatment of these conditions.Cases: Two cases of canine lymphoma associated with possible signs of paraneoplastic peripheral neuropathy were attended at the Veterinary Hospital from the Universidade Federal de Minas Gerais (HV UFMG). Case 1. A spayed mixed breed bitch, with lethargy and unilateral exophthalmos. Brain computed tomography revealed a retrobulbar mass and cytology was diagnostic for extranodal lymphoma. Subsequent to computed tomography, the dog was presented with hypotrophy of the facial musculature and difficulty in grasping food, consistent with trigeminal nerve palsy, which resolved after institution of the 19-week chemotherapy protocol from the University of Wisconsin. Nevertheless, disease reccurred and a rescue protocol was initiated. Case 2. A female Dalmatian, spayed, was diagnosed with multicentric lymphoma, after cytology of the left mandibular lymph node. Chemotherapy was initiated with the same protocol of the previous case. However, the disease progressed and it was observed facial asymmetry with ptosis of the left eyelid, pina and lips, in addition to difficulty in grasping food, suggesting facial and trigeminal cranial nerve palsy. Clinical signs resolved after institution of a rescue chemotherapy protocol. However, in both cases, disease progression and poor clinical condition resulted in decision of euthanasia and necropsy was not authorized.Discussion: Canine lymphoma is often associated with paraneoplastic syndromes, with neuropathy being one of its possible clinical manifestations. In spite of that its pathogenesis remains unclear, with little information in the veterinary literature. Diagnosis is challenging and must be initially based on recognition of neurological clinical signs and lesion localization, as in the reported cases with lesions located on the fifth and seventh cranial nerves. In the patient from the first case, the absence of clinical signs and laboratory abnormalities suggestive of endocrinopathies, associated with neurological signs restricted to the trigeminal nerve, bilaterally, before starting chemotherapy and without the identification of brain lesions in computed tomography, suggested paraneoplastic involvement as the cause of neuropathy. In the second case described, the absence of clinical signs and laboratory abnormalitiess suggestive of endocrinopathies or nutritional deficiencies, associated with neurological signs restricted to the facial and trigeminal cranial nerves, suggested direct or indirect tumour involvement. Both cases showed improvement of neurological clinical signs after chemotherapy which favored the therapeutic diagnosis. Nevertheless, failure to authorize necropsy of patients made it impossible to confirm that peripheral neuropathy is secondary to the remote effect of lymphoma

Epidemiology of Canine Mammary Gland Tumours in Espírito Santo, Brazil

Background: Breast tumours represent about 50 to 70% of all neoplasms in female dogs and their occurrence is directly related to the reproductive status and patient´s age. The purpose of this research was to apply the Brazilian consensus on diagnosis, prognosis and treatment of canine mammary tumours and to and define the regional epidemiological aspects of canine mammary gland tumours in Vitoria metropolitan region (ES, Brazil) between 2012 and 2016 and to correlate the macroscopic characteristics such as lesion size and location of the neoplasm with histopathological diagnosis, tumours grade and lymph node metastasis.Materials, Methods & Results: Data were collected from the archives of the Laboratory of Animal Pathology of UVV and the clinical files of the patients seen in the Veterinary Hospital Prof. Ricardo Alexandre Hippler in 5 years (2012 to 2016). The animals were separated into groups by age to facilitate classification in the group with the highest occurrence of neoplasms. The evaluation of the macroscopic characteristics was performed through the histopathological record described in the pathology laboratory, for each patient, at the time of the initial evaluation. After descriptive analysis, data was correlated using Spearmann test, and frequency dispersion was evaluated using chi-square test, both in the software Graph Pad Prism v. 6.01. This study included 255 bitches and diagnosis of 486 lesions, once 48.6% of the dogs had more than one lesion. 86.8% of lesions were consistent with actual mammary neoplasms, of which 67% were malignant and 20% were benign. Non-neoplastic lesions corresponded to 7.2% of cases and 5.8% were extra-mammary neoplasms, with an increased incidence of lipomas (39.3%) and mast cell tumours (32.1%). Cross-breed dogs represented 26.7% of cases. Poodles (25.5%), Pinschers (9.8%) and Dachshund (4.7%) were overrepresented. Among mammary glands, the most affected with 30.8% and 25.4% were for inguinal and caudal abdominal mammary gland, respectively.Regarding the histopathological grade, 43.7% of the malignant mammary gland tumours were grade I, 40% grade II and 16.2% grade III. The neoplasms smaller than 3 cm in diameter, corresponded to 43.7% malignant neoplasms, of which 75 corresponded to grade I. Those larger or equal to 3-5 cm in diameter corresponded to 22.1% malignant neoplasm, of which 31 corresponded to grade II, and those larger than 5 cm in diameter corresponded to 25.8% malignant neoplasms, of which 34 corresponded to grade II. Macroscopic ulceration was reported in 35/486 neoplasms; of these, 85.7% were malignant. Necrosis was evidenced, microscopically in 11.7% of malignant neoplasms and there was a weak, positive correlation between the occurrence of necrosis and ulceration (P < 0.0001; rs = 0.223), which also correlated with tumour size and histological grade. Of these patients, 24.4% had metastases, and of these, 8.8% presented macroscopic abnormalities in the lymph node. Discussion:Older dogs are at higher risk of developing malignant mammary gland tumour when compared to young bitches, most neoplasms with a histopathological grade III occurred in animals older than 10 years, in agreement with the literature. Age increasing might be related to more biologically aggressive mammary gland tumours. Early neutering is commonly recommended to prevent proliferative abnormalities in the mammary glands, but it has been related to several disorders, and neoplasms, in some breeds. Multiple tumours in more than one mammary gland with different histopathological diagnoses among them, isn’t related to multicentric disease or worse prognosis, as also seen in this survey.Among mammary glands, the inguinal and caudal abdominal are often the most affected,as it was observed in this study; however, no differences were observed in the occurrence of malignant neoplasms, benign or non-neoplastic. Background: Breast tumours represent about 50 to 70% of all neoplasms in female dogs and their occurrence is directly related to the reproductive status and patient´s age. The purpose of this research was to apply the Brazilian consensus on diagnosis, prognosis and treatment of canine mammary tumours and to and define the regional epidemiological aspects of canine mammary gland tumours in Vitoria metropolitan region (ES, Brazil) between 2012 and 2016 and to correlate the macroscopic characteristics such as lesion size and location of the neoplasm with histopathological diagnosis, tumours grade and lymph node metastasis.Materials, Methods & Results: Data were collected from the archives of the Laboratory of Animal Pathology of UVV and the clinical files of the patients seen in the Veterinary Hospital Prof. Ricardo Alexandre Hippler in 5 years (2012 to 2016). The animals were separated into groups by age to facilitate classification in the group with the highest occurrence of neoplasms. The evaluation of the macroscopic characteristics was performed through the histopathological record described in the pathology laboratory, for each patient, at the time of the initial evaluation. After descriptive analysis, data was correlated using Spearmann test, and frequency dispersion was evaluated using chi-square test, both in the software Graph Pad Prism v. 6.01. This study included 255 bitches and diagnosis of 486 lesions, once 48.6% of the dogs had more than one lesion. 86.8% of lesions were consistent with actual mammary neoplasms, of which 67% were malignant and 20% were benign. Non-neoplastic lesions corresponded to 7.2% of cases and 5.8% were extra-mammary neoplasms, with an increased incidence of lipomas (39.3%) and mast cell tumours (32.1%). Cross-breed dogs represented 26.7% of cases. Poodles (25.5%), Pinschers (9.8%) and Dachshund (4.7%) were overrepresented. Among mammary glands, the most affected with 30.8% and 25.4% were for inguinal and caudal abdominal mammary gland, respectively.Regarding the histopathological grade, 43.7% of the malignant mammary gland tumours were grade I, 40% grade II and 16.2% grade III. The neoplasms smaller than 3 cm in diameter, corresponded to 43.7% malignant neoplasms, of which 75 corresponded to grade I. Those larger or equal to 3-5 cm in diameter corresponded to 22.1% malignant neoplasm, of which 31 corresponded to grade II, and those larger than 5 cm in diameter corresponded to 25.8% malignant neoplasms, of which 34 corresponded to grade II. Macroscopic ulceration was reported in 35/486 neoplasms; of these, 85.7% were malignant. Necrosis was evidenced, microscopically in 11.7% of malignant neoplasms and there was a weak, positive correlation between the occurrence of necrosis and ulceration (P < 0.0001; rs = 0.223), which also correlated with tumour size and histological grade. Of these patients, 24.4% had metastases, and of these, 8.8% presented macroscopic abnormalities in the lymph node. Discussion:Older dogs are at higher risk of developing malignant mammary gland tumour when compared to young bitches, most neoplasms with a histopathological grade III occurred in animals older than 10 years, in agreement with the literature. Age increasing might be related to more biologically aggressive mammary gland tumours. Early neutering is commonly recommended to prevent proliferative abnormalities in the mammary glands, but it has been related to several disorders, and neoplasms, in some breeds. Multiple tumours in more than one mammary gland with different histopathological diagnoses among them, isn’t related to multicentric disease or worse prognosis, as also seen in this survey.Among mammary glands, the inguinal and caudal abdominal are often the most affected,as it was observed in this study; however, no differences were observed in the occurrence of malignant neoplasms, benign or non-neoplastic

Secretory carcinoma of the canine mammary gland with nodal and bone metastases: Case report

Background: Secretory carcinoma is a rare histological type of breast neoplasm in humans and dogs that is characterized by the presence of intracellular and extracellular eosinophilic secretions.Case Description: In this case report, we describe the cytological, histological, and immunohistochemical characteristics of secretory mammary carcinoma in a 10-year-old mixed-breed female dog with nodal and bone metastases. The bitch had a history of claudication and a mass in the left humeral scapular region, which revealed osteolysis of the proximal humerus on radiography. Fine-needle aspiration cytology revealed numerous neoplastic cells arranged mostly in cohesive groups but sometimes isolated, that contained cytoplasmic vacuoles and had a moderate-to-high nucleus: cytoplasm ratio with frequent karyomegaly and evident nucleoli. Histologically, the neoplasm was organized in solid, tubular structures with luminal spaces filled with eosinophilic secretions and was composed of cells with clear cytoplasm and prominent vacuoles that pushed the nuclei to the periphery, resembling signet ring cells. The extracellular and intracytoplasmic material of the epithelial cells was positive for periodic acid-Schiff staining and immunoreactive for alpha-lactalbumin. Two chemotherapy sessions were performed, but 1 month after surgery, the clinical condition worsened, and euthanasia was elected, accounting for 133 days of survival after surgical removal of the tumor.Conclusion: The bitch presented with secretory mammary carcinoma with nodal and bone metastases, and histological and immunohistochemical characteristics were important for diagnosis. The morphological and immunohistochemical characteristics of this carcinoma were similar to those observed in humans. Mammary gland secretory carcinoma with bone metastasis must be included as a differential diagnosis among canine mammary gland carcinomas showing cellular morphological characteristics of intracytoplasmic vacuolization and eosinophilic secretion

Sporotrichosis Outburst after Cancer Chemotherapy in a Dog

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

Solitary Osseous Plasmacytoma of a Lumbar Vertebrae with Systemic Involvement in a Dog

Background: Myeloma-related disorders are characterized by proliferation of neoplastic plasma cell or immature immunoglobulin secreting B-lymphocytes, and include multiple myeloma, M-macroglobulinemia and extra-medullary plasmacytoma (cutaneous or extra-cutaneous). Solitary osseous plasmacytoma (SOP) is considered an unique entity among extra-medullary extra-cutaneous plasmacytoma. It is an unusual neoplasia in dogs, predominantly found in middle-aged to older animals, with a higher incidence in bones of axial skeleton. Dogs with vertebral SOP present neurological signs related to spinal cord compression, but progression to multiple myeloma is related to a poor outcome. As in humans, progression to multiple myeloma occurs in most cases, although it may take months or years from its initial presentation. SOP´s biological behaviour, incidence and prognostic are rarely documented. Chemotherapy with melphalan and prednisolone represent the most used protocol for multiple myeloma. However, in SOP, the combination of chemotherapy with local approaches is controversial before the evidence of systemic disease. This paper aims at reporting a case of SOP in a lumbar vertebrae of a dog, with systemic involvement. Case: A 11-year old male mixed breed dog was attended presenting muscle weakness, lethargy, anorexia, adipsia and intense pain manifestation. The dog also presented multiple skin nodules, previously diagnosed as a plasmacytoma, through cytology. The dog´s poor clinical condition and aggressive temper, associated with suspicious of an advanced myeloma-related disorder, resulted in the decision for humanized euthanasia. At necropsy, a pale, friable and hemorrhagic mass was identified on the L3 lumbar vertebrae, associated with an osteolytic bone lesion and spinal cord compression. Histopathological analyses revealed proliferation of plasma cells, with pale perinuclear halo, moderate cellular pleomorphism, 10 binucleated cells and 10 mitotic figures per 10 high power fields, compatible with extramedullary plasmacytoma of the mature type, in the lumbar vertebrae (SOP). It was also seen myeloma-related lesions in the skin and subcutaneous, prostate, heart, superficial mandibular and axillary lymph nodesDiscussion: Solitary osseous plasmacytoma is a myeloma-related disorder rarely reported in dogs. Its biological behaviour is poorly characterized, however progression for multiple myeloma is common in humans and dogs, and it is related to a poor outcome. As the present report, systemic progression of SOP has been previously described and although an overt bone marrow infiltration was not detected, such possibility can not be excluded, once multiple myeloma distribution in the bone marrow is often multifocal. Although chemotherapy is the treatment of choice for multiple myeloma, its indication for SOP is conditioned to the evidence of systemic disease. It might delay tumour progression, but its early implementation may favor the selection of resistant neoplastic clones, making it ineffective when progression to multiple myeloma occurs. In humans radiotherapy is the treatment of choice for SOP, however it may be indicated in association to surgery. A retrospective study showed a higher survival rate in patients with SOP in the axial skeleton, which received surgical treatment combined with radiotherapy, if compared to those treated with surgery or radiotherapy alone. Decision for euthanasia was made based on the suspicious of advanced myeloma-related disorder, patient´s medical condition and aggressive temper, which limited diagnostic investigation and treatment

English (USA)

Background: Tyrosine kinase inhibitors (TKIs) may sensitize neoplasms to conventional antineoplastic agents, however such studies are scarse in the veterinary literature and there is no in vivo study about this subject. Although the literature recommend consensual about the use of masitinib for unresectable or metastatic MCTs, the potential of tumour sensitization to chemotherapeutic agents exerted by the drug is poorly explored in veterinary medicine. The objective of this paper was to report, for the first time, the sensitization of 2 canine mast cell tumours (MCTs) to lomustine, with the use of 2 tyrosine kinase inhibitors: masitinib and toceranib.Cases: Two dogs were referred due tumour recurrence in the left pelvic limb (dog 1), and unilateral mass in the right nasal mucocutaneous region (dog 2). The first case was a 8-year-old female Pinscher, and the second case refers to a 8-year-old male mixed-breed dog. Fine needle aspiration of both lesions was performed, and the cytological analysis were compatible with high grade canine MCT. In the first case, it was started a chemotherapeutic treatment with intravenous vinblastine (2 mg/m²), associated with prednisolone (40 mg/m2, every 24 h for 7 days), followed by 25 mg/m2 every 24 h, for more 30 days, tramadol (4 mg/kg every 8 h, until new recommendations) and gabapentin (3 mg/kg every 12 h, until new recommendations). However, there was no objective response, and vinblastine was substituted by lomustine (60 mg/m2 every 21 days), however there was also no response after 2 doses. After masitinib importation, the same was started at 12.5 mg/kg orally every 24 h, but there was also no objective response. However, after new lomustine administration the lesion showed complete remission. The second dog initiated its treatment with toceranib, recently licensed in Brazil, at a dosage of 2.7 mg/kg every 48 h, and after 30 days, there was partial remission. However, the remaining lesion still deemed unresectable, and systemic chemotherapy with lomustine (50 mg/m2) was initiated along with continuous toceranib. After 3 weeks of the first chemotherapy complete remission was noted and a second dose was administered. Once the patient remained in complete clinical remission, only toceranib was maintained at the same dose. After 11 months using the toceranib, there was sign of disease recurrence and lomustine was re-initiated resulting in complete remission. Discussion: The TKIs masitinib and toceranib might be considered the first-line therapy for unresectable and/or metastatic canine MCT, but also for those cases with confirmed internal tandem duplications in the exon 11 of the c-KIT protooncogene. Masitinib appears to be more selective than others TKI, such as toceranib, imatinib, dasatinib and sunitinib, because it causes weak inhibition of BCR/ABL (breakpoint cluster region-Abelson), Fms (macrophage colony-stimulating factor receptor), Flt-3 (FMS-like tyrosine kinase-3) and VEGFR (vascular endothelial growth factor receptor), which maypartially explains its increased safety and lower risk of cardiotoxicity. In the first case, the animal has been treated with lomustine associated to masitinib and showed a progression-free interval of 33 days, however, the response reported may have been lower, due previously exposition to chemotherapeutic agents, which might compromise the response to TKI. The second case, with the association of lomustine and toceranib, was followed up for 365 days, presenting only one recurrence in the final third of the follow-up, however, with subsequent new complete remission. Sensitization of canine MCT to lomustine with TKIs increases the therapeutic possibilities for this neoplasm, mainly in patients with advanced stage and high-grade tumours.Keywords: dog, mast cell, chemotherapy, masitinib, toceranib

English (USA)

Background: Tyrosine kinase inhibitors (TKIs) may sensitize neoplasms to conventional antineoplastic agents, however such studies are scarse in the veterinary literature and there is no in vivo study about this subject. Although the literature recommend consensual about the use of masitinib for unresectable or metastatic MCTs, the potential of tumour sensitization to chemotherapeutic agents exerted by the drug is poorly explored in veterinary medicine. The objective of this paper was to report, for the first time, the sensitization of 2 canine mast cell tumours (MCTs) to lomustine, with the use of 2 tyrosine kinase inhibitors: masitinib and toceranib.Cases: Two dogs were referred due tumour recurrence in the left pelvic limb (dog 1), and unilateral mass in the right nasal mucocutaneous region (dog 2). The first case was a 8-year-old female Pinscher, and the second case refers to a 8-year-old male mixed-breed dog. Fine needle aspiration of both lesions was performed, and the cytological analysis were compatible with high grade canine MCT. In the first case, it was started a chemotherapeutic treatment with intravenous vinblastine (2 mg/m²), associated with prednisolone (40 mg/m2, every 24 h for 7 days), followed by 25 mg/m2 every 24 h, for more 30 days, tramadol (4 mg/kg every 8 h, until new recommendations) and gabapentin (3 mg/kg every 12 h, until new recommendations). However, there was no objective response, and vinblastine was substituted by lomustine (60 mg/m2 every 21 days), however there was also no response after 2 doses. After masitinib importation, the same was started at 12.5 mg/kg orally every 24 h, but there was also no objective response. However, after new lomustine administration the lesion showed complete remission. The second dog initiated its treatment with toceranib, recently licensed in Brazil, at a dosage of 2.7 mg/kg every 48 h, and after 30 days, there was partial remission. However, the remaining lesion still deemed unresectable, and systemic chemotherapy with lomustine (50 mg/m2) was initiated along with continuous toceranib. After 3 weeks of the first chemotherapy complete remission was noted and a second dose was administered. Once the patient remained in complete clinical remission, only toceranib was maintained at the same dose. After 11 months using the toceranib, there was sign of disease recurrence and lomustine was re-initiated resulting in complete remission. Discussion: The TKIs masitinib and toceranib might be considered the first-line therapy for unresectable and/or metastatic canine MCT, but also for those cases with confirmed internal tandem duplications in the exon 11 of the c-KIT protooncogene. Masitinib appears to be more selective than others TKI, such as toceranib, imatinib, dasatinib and sunitinib, because it causes weak inhibition of BCR/ABL (breakpoint cluster region-Abelson), Fms (macrophage colony-stimulating factor receptor), Flt-3 (FMS-like tyrosine kinase-3) and VEGFR (vascular endothelial growth factor receptor), which maypartially explains its increased safety and lower risk of cardiotoxicity. In the first case, the animal has been treated with lomustine associated to masitinib and showed a progression-free interval of 33 days, however, the response reported may have been lower, due previously exposition to chemotherapeutic agents, which might compromise the response to TKI. The second case, with the association of lomustine and toceranib, was followed up for 365 days, presenting only one recurrence in the final third of the follow-up, however, with subsequent new complete remission. Sensitization of canine MCT to lomustine with TKIs increases the therapeutic possibilities for this neoplasm, mainly in patients with advanced stage and high-grade tumours.Keywords: dog, mast cell, chemotherapy, masitinib, toceranib

Estudo retrospectivo de retrovírus por teste imunoenzimático em gatos na Grande Vitória (ES, Brasil) e neoplasias associadas

As retroviroses encontram-se entre as principais causas de morte em gatos domésticos. Os retrovírus associam-se à célula hospedeira de forma persistente e permanente, levando a quadros clínicos diversos. O vírus da leucemia felina (FeLV) é oretrovírus mais patogênico, com potencial para ocasionar tanto doenças degenerativas e imunossupressão, quanto doenças proliferativas, pois sua associação à célula pode levar ao efeito oncogênico direto. Já o vírus da imunodeficiência felina (FIV), pode levar à clássica síndrome de imunodeficiência, costuma ter um curso crônico, menos agressivo e não possui efeito oncogênico direto. O uso de vacinas e de medidas de controle resultaram em redução da prevalência de FeLV nos Estados Unidos da América (EUA) e Europa, entretanto, no Brasil, determinadas regiões podem apresentar prevalências superiores a 50%. Esse estudo teve como objetivo avaliar a prevalência das retroviroses felinas, pelo teste de ensaio imunoenzimático, na região da Grande Vitória, no Espírito Santo, apontando ainda, a frequência de neoplasias nesses gatos. Um total de 388 gatos foram retrospectivamente avaliados (2014-2016). A prevalência de FIV foi de 2,3% e de FeLV 33,7%. Neoplasias foram identificadas nos três gatos sororeagentes para FIV e FeLV e em três gatos infectados apenas por FIV. Constatou-se a presença de neoplasias ainda em 26,6% dos gatos sororeagentes apenas para FeLV, com destaque para o linfoma na forma mediastinal. A elevada prevalência de FeLV demonstrada neste estudo aponta sobre a necessidade da instituição de medidas efetivas de controle, com destaque para a vacinação