The role of lymph nodes and their drainage in canine mammary gland tumours: Systematic review.

Mammary gland tumours are the most common neoplasms in intact bitches. Over the last decades, veterinary oncology has evolved in detecting and determining the lymph nodes to be removed in these patients for an accurate staging and prognosis, as well as to achieve better disease control and higher overall survival time. Our objective was to describe recent advances related to lymphatic drainage in bitches with mammary gland tumours, focusing on surgery, diagnosis, and prognosis. Through a systematic review using PubMed as the database, a thorough multi-step search reduced 316 studies to 30 for analysis. Vital dyes appear to be crucial in reducing the overall surgery time through transoperative staining of the lymph nodes. Imaging contrasts provide information regarding specific tumour drainage; however, there is still little evidence for their use. The axillary and superficial inguinal lymph nodes are well-established as regional lymph nodes of the cranial and caudal mammary glands. In sequence, accessory axillary, medial iliac, popliteal, and sternal lymph nodes should receive attention if they demonstrate contrast drainage, even considering that the literature has not shown a relationship between drainage and metastasis in these cases. In conclusion, recent studies have provided us with more support in regional lymph node excision regarding the TNM staging system. Studies are highly heterogeneous and method comparisons do not fit due to the non-uniformity of samples, materials, and procedures. We suggest further studies with a larger sample size, complete follow-up of patients, contrast use, and lymph node morphological and immunohistochemical analysis.

Comparison of surgical resection of Axillary Lymph Nodes in Dogs with Mammary Gland Tumors with or without sentinel lymph node visualization with patent blue dye.

Introduction: Dogs' axillary lymph node (ALN) is often difficult to locate before surgical resection. The anatomical location of ALN often discourages Veterinarians from surgical lymphadenectomy. Considering the limited literature available, the actual incidence of metastases and the prognostic relevance are poorly understood. Methods: A non-randomized, prospective clinical study was conducted with female dogs (n = 41) with mammary gland tumor (MGT) in the thoracic or cranial abdominal mammary glands. The study investigated the risks of ALN metastasis based on tumors clinical findings, tumor size, histopathological diagnosis and grade. The main aim of this study was to compare ALN resection with or without patent blue 2.5% (PB) dye injection for sentinel lymph node visualization. A total of 46 mastectomies were performed and five animals underwent two mastectomies. In the first group, 17 patients underwent a mastectomy and lymphadenectomy without PB injection (G1). In contrast, in the second group, 24 patients also received PB injections for sentinel lymph node mapping (G2). The ALN was identified in 38/46 cases (82%). The ALN was identified and excised in only 58% of surgeries in G1(19/46), while in group 2, the lymph node was identified in 92% of the cases and resected in 100% of the cases. The use of PB improves ALN's identification and reduces the surgical resection time in dogs with MGT. Results and discussion: Surgical time differed between the two groups, as it was significantly shorter in the PB injection group compared to group 1 (80 vs. 45 min) (p < 0.0001). The overall frequency of ALN metastasis was 32%. Macroscopic abnormalities in the lymph nodes, tumor size (>3 cm), and diagnosis of anaplastic carcinoma or grade II/III mammary gland tumors were associated with a higher probability of ALN metastasis. Metastases in the ALNs are more common, in dogs presenting with tumors larger than 3 cm and diagnosed with aggressive histological subtypes. The ALNs should be removed for correct staging, prognostic evaluation, and decision for adjuvant therapy.

Extreme lymphocytosis in a dog with T-zone lymphoma.

Background: Canine T-zone lymphoma (TZL) is recognized as an indolent CD45-T cell lymphoma, with low aggressiveness and high overall survival. The diagnosis is obtained by histopathology and immunohistochemistry, but also by cytological examination of the lymph node associated with immunophenotyping. Lymphocytosis is commonly identified as around 10,000 cells/µl and may reach 30,760 cells/µl. Case Description: The present report describes a case of a female Golden Retriever, nine years old, with generalized lymphadenopathy. In the cytological examination of the superficial cervical lymph node, a monomorphic population of small, "clear cells" and "hand mirror" lymphocyte shape was suggestive of TZL. The leukogram showed intense leukocytosis (160,050 cells/µl) due to small clear cell lymphocytosis (152,048 cells/µl). The myelogram showed a myeloid:erythroid ratio of 2:3; with a pyramidal distribution of cell types and the presence of 22.8% of lymphocytes in the differential count. Bone marrow, peripheral blood, and lymph node immunophenotyping resulted in lymphocyte gates with 97.3% to 99.5% CD5+, predominantly CD4-, CD8-, and CD45- confirming the diagnosis of TZL with associated leukemia. Treatment with chlorambucil and prednisolone was started. During the first month, the lymphocytosis remained above 200,000 cells/uL. After four months of treatment, there was a decrease in lymphocytes, which progressively reached a count of 10,800 cells/ul in the eleventh month. Conclusion: In the literature, lymphocytosis above 30,760 cells/µl has not been observed in TZLs. Thus, it is believed that this is the first report of extreme lymphocytosis with a slow response to chemotherapy.

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.

Retrospective study of retroviruses by immunoenzymatic test on cats in Grande Vitória (ES, Brazil) and associated neoplasms.

Retroviruses are among the leading causes of death in domestic cats. Retroviruses associate with the host cell in a persistent and permanent way, leading to diverse clinical conditions. The feline leukemia virus (FeLV) is the most pathogenic retrovirus with the potential to cause both degenerative diseases and immunosuppression, as well as proliferative diseases, as its association with the cell may lead to a direct oncogenic effect. The feline immunodeficiency virus (FIV), in turn, can lead to the classic immunodeficiency syndrome, usually has a chronic, less aggressive course and has no direct oncogenic effect. The use of vaccines and control measures has resulted in a decrease in the prevalence of FeLV in the United States of America (USA) and Europe, however, in Brazil, statistics show prevalence rates above 50%. This study aimed to assess the prevalence of feline retroviruses, by immunoenzymatic assay testing, in the region of Grande Vitória, in Espírito Santo and also point out the frequency of neoplasms in these cats. A total of 388 cats were retrospectively evaluated (2014-2016). The prevalence of FIV was 2.3% and FeLV was 33.7%. Neoplasms were identified in the three cats seropositive for FIV and FeLV and in three cats infected only with FIV. Neoplasms were also found in 26.6% of cats that were seropositive only for FeLV, especially mediastinal lymphoma. The high prevalence of FeLV demonstrated in this study highlights the need for establishing effective control measures, with emphasis on vaccination.

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.