Diagnosis, Prognosis, and Treatment of Canine Hemangiosarcoma: A Review Based on a Consensus Organized by the Brazilian Association of Veterinary Oncology, ABROVET

Hemangiosarcoma is a mesenchymal neoplasm originating in the endothelial cells of blood vessels; they can be classified as non-visceral and visceral types. Non-visceral hemangiosarcomas can affect the skin, subcutaneous tissues, and muscle tissues; visceral hemangiosarcomas can affect the spleen, liver, heart, lungs, kidneys, oral cavity, bones, bladder, uterus, tongue, and retroperitoneum. Among domestic species, dogs are most affected by cutaneous HSA. Cutaneous HSA represents approximately 14% of all HSA diagnosed in this species and less than 5% of dermal tumors, according to North American studies. However, Brazilian epidemiological data demonstrate a higher prevalence, which may represent 27 to 80% of all canine HSAs and 13.9% of all skin neoplasms diagnosed in this species. Cutaneous HSA most commonly affects middle-aged to elderly dogs (between 8 and 15 years old), with no gender predisposition for either the actinic or non-actinic forms. The higher prevalence of cutaneous HSA in some canine breeds is related to lower protection from solar radiation, as low skin pigmentation and hair coverage lead to greater sun exposure. Actinic changes, such as solar dermatosis, are frequent in these patients, confirming the influence of solar radiation on the development of this neoplasm. There are multiple clinical manifestations of hemangiosarcoma in canines. The diagnostic approach and staging classification of cutaneous HSAs are similar between the different subtypes. The definitive diagnosis is obtained through histopathological analysis of incisional or excisional biopsies. Cytology can be used as a presurgical screening test; however, it has little diagnostic utility in cases of HSA because there is a high risk of blood contamination and sample hemodilution. Surgery is generally the treatment of choice for dogs with localized non-visceral HSA without evidence of metastatic disease. Recently, electrochemotherapy (ECT) has emerged as an alternative therapy for the local ablative treatment of different neoplastic types; the use of radiotherapy for the treatment of dogs with cutaneous HSA is uncommon. There is greater consensus in the literature regarding the indications for adjuvant chemotherapy in subcutaneous and muscular HSA; doxorubicin is the most frequently used antineoplastic agent for subcutaneous and muscular subtypes and can be administered alone or in combination with other drugs. Other therapies include antiangiogenic therapy, photodynamic therapy, the association of chemotherapy with the metronomic dose, targeted therapies, and natural products. The benefits of these therapies are presented and discussed. In general, the prognosis of splenic and cardiac HSA is unfavorable. As a challenging neoplasm, studies of new protocols and treatment modalities are necessary to control this aggressive disease.

Quantification of Global DNA Methylation in Canine Mammary Gland Tumors via Immunostaining of 5-Methylcytosine: Histopathological and Clinical Correlations

Mammary tumors are the most prevalent neoplasms in non-neutered female dogs, with genetic and epigenetic alterations contributing to canine mammary carcinogenesis. This study quantified global DNA methylation in 5-methylcytosine (5mC)-immunostained canine mammary tumor samples and established histopathological and clinical correlations. A total of 91 formalin-fixed paraffin-embedded mammary tumor samples from female dogs were retrospectively selected and subjected to immunohistochemistry using an anti-5mC mouse monoclonal antibody. We evaluated 5mC+ stained nuclei of neoplastic epithelial cells in canine mammary glands to obtain semiquantitative histoscores based on staining intensity. Survival rates were estimated based on owners' or veterinary records. Histological samples comprised 28 and 63 benign and malignant canine mammary gland tumors, respectively. Results revealed significant differences between global DNA methylation patterns when mammary samples were categorized as benign or malignant (p = 0.024), with hypomethylated patterns more prevalent in malignant tumors and those with higher relapse behavior (p = 0.011). Of note, large diameter (>5 cm) tumors revealed a lower methylation pattern (p = 0.028). Additionally, we found non-statistically significant differences when tumors were grouped by histopathological characteristics, clinical parameters, or survival. These findings propose global DNA methylation assessment as a promising tool for detecting canine mammary tumors with relapse propensity.

Cardiac lymphoma in dogs –

Lymphoma is a very common lymphoid malignancy in dogs, but cardiac involvement is rare. Primary cardiac lymphoma is defined as lymphoma involving the heart, the pericardium, or both, and is classified as extranodal anatomical form. The present report describes the cases of three animals with cardiac lymphoma. All cases presented moderate to severe pericardial effusion and cardiac tamponade. The cytological analysis of the effusion was consistent with the diagnosis of cardiac lymphoma. The anatomopathological evaluation of the tumor extracted from the heart of one of the animals, after euthanasia, was consistent with cardiac lymphoma. The other two animals were treated with Madison-Wisconsin chemotherapy protocol and survived between 6 to 8 months. This report emphasizes the importance of pericardial effusion cytology for the diagnosis, appropriate treatment approach and monitoring of cardiac tumors in dogs and cats.

Canine mammary tumors in Santos, Brazil: clinicopathological and survival profile

Os tumores das glândulas mamárias são as neoplasias mais comuns em cadelas em nosso país; no entanto, são poucos os trabalhos brasileiros dedicados ao estudo clinicopatológico e de sobrevida nesta doença. O presente trabalho teve por objetivo o estudo clínico e patológico dos tumores mamários caninos na Região Metropolitana de Santos, uma área no estado de São Paulo com uma população canina estimada em 120 mil animais. Dados de 14.298 cães foram coletados retrospectivamente dos prontuários médicos do Hospital Veterinário da Universidade Metropolitana de Santos – São Paulo – Brasil. Durante o período do estudo, foram atendidas 317 fêmeas com diagnóstico histopatológico de neoplasia, dos quais, 170 se referiam a lesões mamárias epiteliais distribuídas em 13 tumores benignos, 152 malignos (89,4% dos diagnósticos) e 5 lesões epiteliais não-neoplásicas (hiperplasia ductal). O tumor mais frequente foi o carcinoma tubular (38,2% dos tumores malignos) e tumores de grau I, respondendo por 73,0% do total diagnosticado. Estudos de sobrevida apontaram para o estadiamento clínico das neoplasias mamárias caninas como importante fator prognóstico, e na análise multivariada, diâmetro do tumor, grau histológico, quimioterapia adjuvante e recorrência apresentaram-se como covariáveis com valor preditivo de sobrevida. Levando-se em conta a elevada prevalência de carcinoma tubular simples na população canina de Santos, pode-se considerá-la como promissor modelo translacional para o estudo da doença.