Clinic-Pathological Aspects of Spleen Hemophagocytic Histiocytic Sarcoma in a Dog

Background: Histiocytes are cells that differentiate into macrophages and dendritic cell lines from bone marrow CD34+ stem cells. The hemophagocytic histiocytic sarcoma (HHS) is the only malignant neoplasm originating from macrophage lineages, being a variation of histiocytic sarcoma (HS), originated from dendritic cells. In general, the HHS shows aggressive biological behavior, due to the erythrophagocytosis characteristic of this disease and overall average survival around seven weeks, affecting mainly Bernese Mountain Dog, Rottweiler and Golden Retriever breeds. Therefore, the objective of this work is to report the case of a dog with HHS, emphasizing the clinical aspects and its diagnostic method.Case: An 8-year-old bitch Rottweiler, was attended with history of inappetence and prostration. The complete blood count showed normochromic normocytic anemia, monocytosis and thrombocytopenia, with serum urea levels below the reference value for the specie in the biochemical examination. The abdominal ultrasound highlighted splenomegaly, with heterogeneous parenchyma and presence of a vascularized mass and an enlarged splenic vein.  Thoracic radiographic examination showed multifocal and rounded radiopaque structures in the pulmonary parenchyma, suggesting metastatic formation. Rapid serological tests for detection of the main hemoparasitosis antibodies were negative, as well as negative Coombs test. The animal was submitted to exploratory laparotomy with medial line access and posterior splenectomy. The spleen microscopic evaluation revealed neoplastic proliferation cells in mantle arrangement and solid nests areas, supported by a fine fibrovascular stroma. The cells had broad and eosinophilic cytoplasm, round nuclei and some pleomorphism, rude chromatin and evident nucleoli. It was also observed the presence of marked anisocytosis and anisocariosis, hemophagocytic activity, and 27 mitoses in 10 fields (40 x). There were atypical mitoses and necrosis and extensive hemorrhaged areas. These histopathological findings suggested a histiocytic malignant neoplasia and immunohistochemical analysis   was performed to define a better histiocytic neoplasm origin. The neoplastic cells showed positive imunostaining for CD11d and Iba1 and negative imunostaining for CD3 and CD20, as well as a proliferative index of 80%, supporting the diagnosis of HHS in the animal's spleen. The following hematological analyzes demonstrated persistence of anemia, worsening of thrombocytopenia, prolongation of activated partial thromboplastin time, hypoproteinemia with hypoalbuminemia, serum increase of creatinine, alkaline phosphatase and total bilirubin. Myelogram showed erythrocyte and granulocytic lineage hypoplasia, thrombocytic aplasia and more than 50% of macrophages in bone marrow cell population. The animal’s clinical condition worsened rapidly, after successive transfusions and administration of chemotherapy with lomustine, leading to death 14 days after the surgery.Discussion: HHS is the most serious clinical presentation among histiocytic disorders, conferring an extremely unfavorable prognosis. In addition, the scientific literature that specifically addresses the HHS is rare, with therapeutic extrapolations being performed for the treatment of HS from dendritic cells. The racial predisposition and clinical findings, associated with hematological changes, histopathological analysis and confirmation by immunohistochemistry allowed the diagnosis of HHS, a rare and underreported neoplasm, with aggressive biological behavior and with still inefficient treatment in veterinary medicine

Função pulmonar em mulheres com câncer de mama submetidas à radioterapia: um estudo piloto

O câncer de mama é a forma de câncer que mais causa mortes entre mulheres no Brasil. O tratamento consiste em intervenção cirúrgica, quimioterapia, hormonioterapia e radioterapia, esta última responsável por uma significativa diminuição na taxa de recorrência local do câncer, mas que pode afetar a função pulmonar. O objetivo deste estudo foi detectar alterações pulmonares funcionais decorrentes da radioterapia no tratamento do câncer de mama. Participaram do estudo 10 mulheres submetidas a tratamento do câncer de mama, avaliadas quanto à função pulmonar antes e após a radioterapia. Foram mensuradas capacidade inspiratória e capacidade vital forçada, por espirômetro de incentivo, e pressões inspiratória e expiratória máximas, por manovacuômetro. Embora tenha havido redução, em vários casos, dos valores medidos antes e depois da radioterapia, não foi encontrada diferença estatisticamente significativa. Nas pacientes avaliadas, pois, a radioterapia não parece ter prejudicado a função pulmonar.Breast cancer is the cancer that most causes death among women in Brazil. The treatment consists in surgery, chemotherapy, hormontherapy, and radiotherapy, the latter being responsible for important decrease in recurrence rates, though it may affect pulmonary function. The aim of this study was to detect lung function changes due to radiotherapy in breast cancer treatment. Ten women who were undergoing breast cancer treatment were assessed as to pulmonary function before and after radiotherapy. Measurements taken were inspiratory capacity and forced vital capacity, by means of incentive spirometer, and maximum inspiratory and expiratory pressures, using a pressure meter. Though in many cases measures found after radiotherapy were lower, no significant difference could be found. Thus radiotherapy did not seem to affect lung function in the assessed sample of women with breast cancer

Pulmonary function in women with breast cancer undergoing radiotherapy: a pilot study

O câncer de mama é a forma de câncer que mais causa mortes entre mulheres no Brasil. O tratamento consiste em intervenção cirúrgica, quimioterapia, hormonioterapia e radioterapia, esta última responsável por uma significativa diminuição na taxa de recorrência local do câncer, mas que pode afetar a função pulmonar. O objetivo deste estudo foi detectar alterações pulmonares funcionais decorrentes da radioterapia no tratamento do câncer de mama. Participaram do estudo 10 mulheres submetidas a tratamento do câncer de mama, avaliadas quanto à função pulmonar antes e após a radioterapia. Foram mensuradas capacidade inspiratória e capacidade vital forçada, por espirômetro de incentivo, e pressões inspiratória e expiratória máximas, por manovacuômetro. Embora tenha havido redução, em vários casos, dos valores medidos antes e depois da radioterapia, não foi encontrada diferença estatisticamente significativa. Nas pacientes avaliadas, pois, a radioterapia não parece ter prejudicado a função pulmonar.Breast cancer is the cancer that most causes death among women in Brazil. The treatment consists in surgery, chemotherapy, hormontherapy, and radiotherapy, the latter being responsible for important decrease in recurrence rates, though it may affect pulmonary function. The aim of this study was to detect lung function changes due to radiotherapy in breast cancer treatment. Ten women who were undergoing breast cancer treatment were assessed as to pulmonary function before and after radiotherapy. Measurements taken were inspiratory capacity and forced vital capacity, by means of incentive spirometer, and maximum inspiratory and expiratory pressures, using a pressure meter. Though in many cases measures found after radiotherapy were lower, no significant difference could be found. Thus radiotherapy did not seem to affect lung function in the assessed sample of women with breast cancer

Canine Mammary Neoplasms - Evaluation of Tumor Microenvironment

Background: The tumor microenvironment is an important target of studies in different types of neoplasms. Understanding the role of general components such as immune, vascular and fibroblastic cells has the objective of contributing to prognosis and treatment. The aim of this study was to evaluate the relationship between mast cells and angiogenesis in benign and malignant mammary neoplasms by investigating the role of degranulation and microlocation of mast cells and neoformed vessels in canine mammary neoplasms.Materials, Methods & Results: Mammary glands (n = 122) from 50 female dogs submitted to mastectomy without chemotherapy were evaluated and categorized into 3 groups: control group (n = 46); malignant group (n = 57) and benign group (n = 19). Lymph nodes without changes (n = 59) and with metastases (n = 6) were also evaluated. To evaluate the MCD (mast cell density) and angiogenesis, Toluidine Blue (0.1%) and Gomori’s Trichrome techniques were performed and adapted from previous studies. Photomicrographs of 10 hotspot areas on a 40x objective lens of the mammary glands and lymph nodes were captured to assess MCD and angiogenesis. In the absence of these areas, random fields were captured. For the mammary glands of the malignant and benign groups, 20 fields were analyzed, as the analysis considered the microlocation (peritumoral and intratumoral). Counting was performed manually using ImageJ software version 1.42q by 2 observers. The statistical analysis were performed using SPSS software version 19.0. The most frequent histological type in the malignant group was carcinoma in mixed tumor (68.42%; 39/57) and in the benign group was benign mixed tumor (57.89%; 11/19). Female dogs without breed pattern were more frequently affected represented 70% of the animals and the mean age was 9 years and 8 months ± 3 years and 1 month. The granulated density of mast cells and peritumor vessels was higher in the malignant group (P = 0.03; P = 0.02). There was also a positive correlation between intratumor and total vessel density and mast cell density. There was no significance between the malignant and benign groups in regard with fibrosis density.Discussion: In this study were observed a greater density of blood vessels in malignant group, suggesting the participation of blood vessels for neoplastic proliferation. Furthermore, these vessels were located in the peritumoral region as in previous studies. The positive correlation between MCD and blood vessels was similar to a previous study performed in canine breast carcinomas and breast cancer in women. Regarding microlocation, another study also found higher MCD in the peritumoral region than in the intratumoral region of canine carcinomas. Although there are already studies for this purpose in cases of oral squamous cell carcinoma in humans, we believe this is the first study to investigate the role of mast cell degranulation in mammary neoplasm of bitches. The MCD was not significant among the malignant and benign groups and in the mammary glands of the control group the MCD was higher, as observed by other studies. Future studies should be associated the survival time and the presence of metastases in order to confirm the findings. In view of these findings, we may conclude that a higher density of mast cells is related to a higher density of blood vessels and that these are more abundant in malignant neoplasms, which reinforces the crucial role of angiogenesis in the neoplastic development.Keywords: tumor microenvironment, mammary tumor, mast cells, angiogenesis, bitches

Extraskeletal Osteosarcoma in the Duodenum of a Dog

Background: Osteosarcoma is the most observed primary bone tumor in dogs, and may affect the appendicular and axial skeletons. In addition, it may be present in extraskeletal form, accounting for only 1% of cases. As shown by few reports in the literature, the involvement of the intestinal region by is rare. The objective of this study was to report the case of a 13-year-old Yorkshire dog, submitted to an exploratory laparotomy for suspected partial intestinal obstruction, diagnosed with extraskeletal osteosarcoma. Case: A 13-year-old dog, Yorkshire Terrier, male, presented clinical signs of gastrointestinal abnormalities. An ultrasound examination was performed and was found a mass in small intestine region with wall and lumen invasion. Then, was realized exploratory laparotomy and detected intestinal obstruction due to a mass with approximately 5.0 x 6.0 x 4.4 cm localized in duodenum. Surgical removal was performed and the sample sent to the veterinary diagnostic laboratory for histopathological examination. The sample had an irregular surface and firm consistency. In addition, when cut, the mass enveloped the intestinal layers and sometimes obstructed the lumen. Then, the sample were processed routinely for histopathology. After that, in microscopy evaluation was detected cell proliferation, affecting all layers of intestine. In detail, cells were elongated with pleomorphism marked and atypical mitosis. In addition, there was production of cartilage and bone matrix. So, sue the absence of others sites, the neoplasm was considered primary of intestine. After that, to evaluate the expression of KI-67 and COX-2 was performed, and the cell proliferation index was 54.0% and the COX-2 expression was moderate in less than 10% of neoplastic cells. After the surgery, the patient was hospitalized for a week and continue the treatment in home. Afterwards, the tutor received the diagnosis, but even though he was instructed on the severity of the case, he chose not to undergo chemotherapy. After three months, the patient presented abdominal fluid and nodules in your liver, suggesting metastasis, but without diagnosis confirmation. The patient died five months after the diagnosis of extraskeletal osteosarcoma. However, no necropsy was realized, impossibility the diagnosis confirm. Discussion: The frequency of extraskeletal osteosarcoma in dogs remains unknown, with the mammary glands being the most affected site. In the present study, osteosarcoma affects the duodenal region and no reports of this neoplasm in the duodenum of dogs have been found in the literature. The clinical sign of dyschezia was important for the tutor to refer the animal to the veterinarian and perform the ultrasound in an attempt to elucidate the case, as the tumor mass is not always palpable. Histopathological examination and immunohistochemistry were necessary for the differential diagnosis and to establish the prognosis, although after the surgery the tutor chose not to perform chemotherapy. Extraskeletal osteosarcoma are usually highly metastatic, mainly affecting the lymph nodes and liver. In this case, the patient presented a liver nodule three months after the tumor removal surgery, but unfortunately, there was no diagnostic confirmation. Such neoplastic type is rarer and more aggressive than appendicular and axial OS, with an average survival of 1 to 3 months. In this case, as a necropsy was not obtained, we cannot attribute the survival time to the disease. The survival rates of osteosarcomas in dogs are few months, but in the present case, although the patient died five months after surgery, the failure to perform a necropsy compromises the attribution of survival time to extraskeletal osteosarcoma. Keywords: canine, neoplasm, histopathology, immunohistochemistry

Histomorphological and Immunophenotypic Characterization of Feline Injection Site-Associated Sarcoma

Background: Feline Injection Site-Associated Sarcoma (FISS) is a mesenchymal neoplasia of aggressive behavior that develops in sites where vaccine or drugs were administered. FISS is clinically characterized by the appearance of a solitary firm nodule or a diffuse mass, adhered to tissues, in regions associated to vaccine or drug applications. Despite low prevalence, tumor recurrence rates can reach 80%. FISS present more aggressive histological characteristics when compared to sarcomas not associated to injection sites. The aim of this paper is to contribute towards the understanding of the biological behavior of FISS.Materials, Methods & Results: Sixteen samples of FISS were analyzed. Fibrosarcomas were the most frequent histological subtype (62.5%). Malignant peripheral nerve sheath tumor was diagnosed in 18.75% cases. Ten (62.5%) FISS were classified as grade II; 4/16 (25%) grade I, and 2/16 (12.5%) grade III. Cox-2 overexpression occurred in 3/16 (18.75%) samples, with positive correlation between Cox-2 expression and cellularity (r = 0.696, P = 0.003). Mitotic index lower than 9 events was found in 11/16 (68.7%) samples and between 10 and 19 mitotic events in 5/16 (31.3%) cases. Mean Ki-67 expression was 2.39 ± 2.48%. FISS characterized as fibrosarcomas presented longer overall survival (median 545 days) than other histological subtypes (median 130.5 days) [P = 0.01].Discussion: Patients with FISS generally present with larger nodules than those with sarcomas not associated to injections, suggesting a challenge for pet owners to note subcutaneous tumors in the interscapular region, in addition to the aggressive biological behavior of FISS. The influence of size on prognosis remains controversial. An association between histologic grade and the development of metastasis has been observed, with patients with grade III FISS associated with an increase in the metastatic rate. The present study did not find a correlation between overall survival and histologic grade. A positive correlation between the presence of giant multinucleated cells and tumor grade has been observed.Despite the absence of such correlation in the present study, possibly due to a small sample, a trend for higher frequency of giant cells in advanced histologic grade was observed. Cox-2 expression in 81.75% and overexpression in 18.75% of our samples contrasts with the 64% Cox-2 expression and the absence of Cox-2 expression found by other authors. A positive moderate correlation between cellularity and Cox-2 expression was also observed, while another study did not find a correlation of Cox-2 expression with tumor grade, recurrence rates or overall survival. Cox metabolites such as prostaglandins can enhance cellular proliferation, inhibit apoptosis, induce angiogenesis, alter cellular adherence to facilitate metastatic development and inhibit immune surveillance. In the present study, no correlation was found between Cox-2 and angiogenesis in FISS. Our findings demonstrated low immunolabeling for Ki-67. A previous study analyzed 52 samples of FISS, 51% of them considered grade III, with a mean Ki-67 labeling of 14%. The lower Ki-67 staining in the samples of the present study may be related to the lower number of samples of grade III FISS or to a difference in the studied population. Fibrosarcomas are associated with better prognosis than other histological subtypes. Furthermore, malignant peripheral nerve sheath tumors were diagnosed as a possible histological subtype of FISS

Canine Mammary Mixed Tumours: A Review

Mammary mixed tumours are the most frequent neoplasias in female dogs. In humans, mixed tumours are frequently found in the salivary glands and are known as pleomorphic adenomas. In addition to their histomorphologic similarities, mixed tumours and pleomorphic adenomas have the potential to become malignant and give rise to carcinomas in mixed tumours and carcinomas ex-pleomorphic adenoma, respectively. The factors associated with malignant transformation are still poorly known in the case of canine mixed tumours. However, this form of neoplasia tends to be associated with a better prognosis than other malignant histological types. This paper discusses the main features associated with female canine mammary mixed tumours

USO DE IMAGENS DE MICROSCOPIA DIGITAL NO ENSINO DE CIÊNCIAS BIOLÓGICAS: AVALIAÇÃO DA MOTIVAÇÃO E DA PROFICIÊNCIA DE ESTUDANTES DO ENSINO MÉDIO

The teaching of Biology in schools is very important in the education of students, as it contributes to the development of a solid and comprehensive understanding of living beings  and the biological processes that occur in the natural world. The importance of Biology can be highlighted in three main aspects: scientific knowledge, student motivation and practical classes. Considering these aspects, the objective of this study was to evaluate the effects of using digital microscopy and printed boards in Biology classes, for high school students, in relation to motivation and immediate learning. The methodology involved a theoretical class on the chosen topic, which was HPV and cervical cancer, followed by practical classes using digital microscopy images and printed plates. Students responded to tests and an understanding that assessed learning and motivation after the interventions. The study allowed us to verify that students' motivation is greater when there is a practical part and the use of microscope images to relate the content, digital microscopy and printed slides cause a high motivation in students who do not have experience and the importance of developing innovative and facilitating tools in the teaching of Biological Sciences. Thus, it is concluded that microscopy, in both forms used in the experiment, is a motivating factor and has a favorable cost, leaving the school to opt for the use of printed boards or digital microscopy, considering its reality.La enseñanza de la Biología en las escuelas es muy importante en la formación de los estudiantes, ya que contribuye al desarrollo de una comprensión sólida e integral de los seres vivos y de los procesos biológicos que ocurren en el mundo natural. La importancia de la Biología se puede destacar en tres aspectos principales: el conocimiento científico, la motivación del estudiante y las clases prácticas. Considerando estos aspectos, el objetivo de este estudio fue evaluar los efectos del uso de microscopía digital y pizarras impresas en clases de Biología, para estudiantes de secundaria, en relación con la motivación y el aprendizaje inmediato. La metodología implicó una clase teórica sobre el tema elegido, que fue el VPH y el cáncer de cuello uterino, seguida de clases prácticas utilizando imágenes de microscopía digital y placas impresas. Los estudiantes respondieron pruebas y un cuestionario que evaluó el aprendizaje y la motivación después de las intervenciones. El estudio permitió comprobar que la motivación de los estudiantes es mayor cuando existe una parte práctica y el uso de imágenes microscópicas para relacionar el contenido, la microscopía digital y las láminas impresas provocan una alta motivación en los estudiantes, no mostrando diferencias significativas y la importancia del desarrollo. de herramientas innovadoras y facilitadoras en la enseñanza de las Ciencias Biológicas. Así, se concluye que la microscopía, en las dos formas utilizadas en el experimento, es un factor motivador y tiene un costo favorable, dejando a la escuela optar por el uso de placas impresas o microscopía digital, considerando su realidade.O ensino de Biologia nas escolas é muito importante na formação dos estudantes, pois contribui para o desenvolvimento de uma compreensão sólida e abrangente dos seres vivos e dos processos biológicos que ocorrem no mundo natural. A importância da Biologia pode ser destacada em três aspectos principais: conhecimento científico, motivação dos estudantes e aulas práticas. Considerando esses aspectos, o objetivo deste estudo foi avaliar os efeitos da utilização de microscopia digital e de pranchas impressas nas aulas de Biologia, para alunos de ensino médio, em relação à motivação e à aprendizagem imediata. A metodologia envolveu uma aula teórica sobre o tema escolhido que foi HPV e câncer de colo de útero seguida de aulas práticas com o uso de imagens de microscopia digital e de pranchas impressas. Os estudantes responderam a testes e a um questionário que avaliaram aprendizagem e motivação após as intervenções. O estudo permitiu verificar que a motivação dos estudantes é maior quando se tem uma parte prática. Já o uso de imagens de microscópios para relacionar o conteúdo, a microscopia digital e as lâminas impressas causam uma motivação elevada nos estudantes, não apresentando diferenças significativas e a importância do desenvolvimento de ferramentas inovadoras e facilitadoras no ensino de Ciências Biológicas. Dessa forma, conclui-se que a microscopia, em ambas as formas utilizadas no experimento é um fator motivador e de custo favorável, cabendo a escola optar pelo uso das pranchas impressas ou microscopia digital, considerando a sua realidade

Solid Iridociliary Carcinoma in a Dog

Background: Iridociliary epithelial tumors (ICETs) originate from the iris epithelium or ciliary body. They comprise ciliary body adenoma, carcinoma, pleomorphic adenocarcinomas, medulloepitheliomas, and other primitive neuroectodermal tumors. They are the second most common primary intraocular tumors in dogs and have already been reported in sheep and humans. In dogs, they occur more frequently in middle-aged to elderly animals, and the Labrador and Golden Retriever seem to be more predisposed breeds. This study aimed to describe the clinical and pathological aspects of solid iridociliary carcinoma in a dog. Case: A 3-year-old Poodle bitch was treated for discomfort in the left eyeball region, increased intraocular pressure and moderate buphthalmia. A direct ophthalmological examination was performed without equipment, and a mass was visualized in the posterior chamber, distorting the pupillary cleft. We opted for unilateral enucleation and forwarded the material for histological analysis. Macroscopically, the eyeball measured 3.4 cm (anteroposterior) x 2.6 cm (vertical), with a brownish mass that occupied the entire anterior chamber and part of the posterior chamber. Histologically, there was a neoformation in the ciliary body and iris pigment epithelium, partially well-delimited and densely cellular. The neoplasm was organized into predominantly solid formations interspersed with a discrete amount of blood vessels, rare bundles of fibrous stroma, and amorphous eosinophilic material forming membranes that were positive for PAS. Sections of the neoplasm were subjected to immunohistochemistry using anti-cytokeratin AE1/AE3, anti-S100 protein, anti-vimentin, and anti-Ki-67. Positive cytoplasmic immunostaining for cytokeratin and S-100 was observed. Only 45.6% of cells were positive for Ki-67 (500 cells). No immunostaining was observed for vimentin. Discussion: The diagnosis of solid iridociliary carcinoma was based on the histological features and positive immunostaining for cytokeratin AE1/AE3 and protein S100. Iridociliary carcinomas present positive immunostaining for cytokeratin, whereas adenomas and normal iridociliary epithelium do not present this immunostaining. Moreover, the high rate of cell proliferation was indicative of malignant neoplasia, as observed by the high mitotic count and high positivity for Ki-67. The S100 protein helped in the diagnosis of ICETs, as the iridociliary epithelium showed positive staining for this protein. Some histological features are important to consider in the diagnosis of iridociliary tumors in dogs, such as noninvasive growth in the posterior chamber, pigment epithelium, and thick homogeneous membranes on the cell surface. Furthermore, the presence of positive PAS membranes favors the diagnosis of iridociliary epithelial tumors. ICETs must be differentiated from melanocytomas, anterior uveal melanoma, medulloepitheliomas, and metastatic and pleomorphic carcinomas. The histological characteristics, especially the presence of PAS-positive membranes, associated with the immunohistochemical profile of neoplasm cells, help differentiate the ICETs from these tumors. In general, the prognosis is poor for eyeball and vision maintenance in canine iridociliary tumors, and scleral invasion is associated with a higher recurrence rate.   Keywords: neoplasm, eye, immunohistochemistry, cytokeratin, S100 protein

Paraneoplastic Hypercalcemia Secondary to Canine Mammary Tumors

Background: Paraneoplastic syndromes are complexes symptom that occur at a distinct site from the primary tumor or its metastasis by the production of hormone by the tissue in which the tumor appears. Paraneoplastic hypercalcemia is associated with an abnormal elevation of serum calcium levels and the mainly tumor related to this syndrome in canine is lymphoma, anal sac apocrine gland adenocarcinoma and multiple myeloma. In mammary tumors, the most frequent tumor that affect female dogs, this syndrome was also observed. The aims of this study were to evaluate serum calcium levels in female dogs with malignant mammary tumors and correlate calcium levels with clinicopathological parameters.Materials, Methods & Results: It was evaluated fifty-one female dogs with mammary carcinomas (simple carcinomas and carcinoma in mixed tumors) for serum calcium levels using colorimetric test. Clinical-histopathological data as spray status, pseudopregnancy, tumor size, ulceration, clinical staging, histopathological type and tumor grade were also evaluated in association with serum calcium levels. All dogs were treated with unilateral mastectomy. It was observed that 18 animals (35%) had calcium serum levels increased (>11.5 mg/dL) and 56% (10/18 cases) of these animals had serum calcium levels higher than 12 mg/dL. All dogs with hypercalcemia were asymptomatic, including two female dogs that presented the highest levels (13.43 mg/dL and 14.28 mg/dL). Hypercalcemia of malignancy was related to mammary carcinomas after the exclusion of other causes of hypercalcemia through laboratory tests (complete blood count and serum biochemistry) and abdominal ultrasound. No correlation was verified between the corrected serum calcium values with clinical and histopathological parameters evaluated.Discussion: In this study, it was observed a high incidence of paraneoplastic hypercalcemia associated with canine mammary tumors (35%). In humans, this syndrome is related in up to 10% of all patients with advanced cancer and with worse prognosis. The most frequent clinical signs of hypercalcemia are nonspecific and can be confused with other diseases, such as polyuria, polydipsia, anorexia, constipation, lethargy and weakness. The treatment of this syndrome is based on tumor resection and when necessary other treatments can be performed with fluid containing 0.9% sodium chloride, furosemide, prednisolone and calcitonin. Patients with asymptomatic or mildly symptomatic hypercalcemia (calcium levels <12 mg/ dL) do not require immediate treatment. Clinical signs occur more frequently with serum calcium levels higher than 15 mg/dL. Calcium levels higher than 18 mg/dL are considered a medical emergency and the clinical signs observed are trigger seizures, cardiac arrhythmia, acute renal failure and death. Most animals of this study presented mild hypercalcemia, that could justify the absence of clinical signs related to this syndrome, and the treatment for this syndrome was the tumor removal. The high serum calcium levels did not show correlation with more aggressive tumors and poorer prognosis, conditions evaluated by histological type, tumor grade and clinical stage. The evaluation of serum calcium levels is an important clinical test to be done in female dogs with mammary tumors, besides to be an affordable and technically simple test. The clinical signs related to this syndrome are nonspecific and may be confused with other diseases commonly observed in older dogs. The data suggest that there are no correlation between serum calcium levels with aggressiveness of canine mammary tumors and with other clinical features