Intermuscular Lipoma in Dogs

Background: Lipoma is a benign tumor composed of mature adipose tissue commonly found in subcutaneous tissues. However, eventually, lipomas may be located between the muscle fasciae being classifed as intermuscular lipomas. Complete surgical resection of the tumor mass is indicated as a treatment of affected patients.This report describes fve cases of intermuscular lipoma in dogs, due to the scarcity of data in the literature and lipoma relative importance in the clinical and surgical routine.Case: Five dogs were presented with a history of a large volume in the limbs with progressive growth, suggesting the presence of neoplasia. The frst step was to conduct anamnesis, when the owner reported slow growth, absence of pain, limping and licking of site. No other change was observed upon physical examination. Complete blood count (CBC) as well as liver assessment (FA) and renal (creatinine) were performed in all patients, and the results showed no changes. Fine needle aspiration cytology (FNAC) was performed and showed cells from adipose tissue, followed by histopathological examination of the lesions. Histopathological examination after incisional biopsy of the tumors showed malignancy-freetissue, composed of adipocytes without atypia, interspersed with fbrovascular stroma, confrming the lipoma diagnosis.Intermuscular lipomas were diagnosed in fve dogs with a history of a large volume in the limbs with progressive growth; all of them underwent bloc resection of the tumors. In all cases, the intermuscular lipomatous tumors were well-circumscribed and easily isolated from the tissues.Discussion: Although lipomas are relatively common in older dogs, especially in the subcutaneous tissue, intermuscular subtype is rare in veterinary medicine, which justifes the report of these cases. Intermuscular lipomas account for only 0.3% of the occurrences in human medicine. Morphologically described as tumors of slow and progressive evolution, typically reaching sizes up to 2 cm in humans, the particular cases of tumor masses greater than 5 cm are called giant lipomas. Theslow development of intermuscular lipomas has also been described in domestic animals by, thus corroborating the clini cal history in this work. The intermuscular septum is considered as the origin of intermuscular lipoma, with subsequent development of the adipose tissue between adjacent muscle bundles, thus, resulting usually in well-circumscribed mass of easy surgical divulsion. The morphological characteristics of the resected lipomas, as well as the simple surgical technique corroborate descriptions in the literature. Intermuscular lipomas consist of a challenging diagnosis despite attracting little attention from surgeons. The possibility of the mass being malignant, such as liposarcoma, should also be consideredsince the clinical symptoms consist of swelling of the deep soft tissues. The diagnosis for all these patients was obtained by histopathological examination, since the simple observation of the clinical fndings alone does not support the tumor diagnosis. Lipoma and liposarcoma should be differentiated by cytological and histopathological evaluations of the neoplasia, whereas infltrative lipomas can be diagnosed based on diagnostic imaging methods or even on the fndings during surgery. In this report, specifcally, the fndings during surgery contributed to the differentiation between infltrative and intermuscular lipoma, while for malignancy rating all patients underwent cytological and histopathological evaluations asindicated in the literature. In conclusion, this study demonstrated that complete resection of intermuscular lipoma proved to be an effective treatment to cure the patients.Keywords: benign neoplasm, surgery, resection of intermuscular, canine

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

Linfoma cutáneo tarsal en gato – estudio de caso

Lymphoma is the most common lymphoproliferative disorder in cats. Cutaneous lymphoma, however, is a rare form of extranodal lymphoma. Recently, several cutaneous lymphomas at the tarsal region have been reported in cats. As it differs clinically and histopathologically from the common cutaneous lymphoma, it was denominated cutaneous tarsal lymphoma. The present study describes the case of a 13-year-old male domestic longhair cat that presented with a subcutaneous mass, of 30-days evolution, at the tarsal region of the right pelvic limb. Histopathology analysis showed malignant neoplasia of round cells, morphologically suggestive of large cell lymphoma. Immunohistochemistry confirmed the diagnosis of B-immunoblastic lymphoma. Patient was treated with lomustine, and prednisolone with an overall survival time of 2.1 months. The aggressiveness of this feline lymphoma reinforces the need for further studies to understand better the disease progression and to establish improved therapeutic protocols that can increase survival time and improve quality of life of these patients.El linfoma representa la enfermedad linfoproliferativa más frecuente en gatos. Sin embargo, el linfoma cutáneo es una rara forma de linfoma extranodal. Recientemente, el linfoma cutáneo se reportó localizado en el tarso. Tanto clínica como histopatologicamente, esta forma difiere de la forma cutánea típica, y se denominó linfoma tarsal felino. Este estudio describe el caso de un gato, doméstico de pelo largo, 13 años de edad con una masa subcutánea, de 30 días de evolución en la región tarsal del miembro pélvico derecho. La histopatologia reveló neoplasia de células redondas, sugestiva de linfoma de células grandes. La inmunohistoquímica confirmó el diagnóstico de linfoma imunoblástico de células B. El tratamiento realizado fue lomustina y prednisolona con tiempo de sobrevida de 2,1 meses. La agresividad de este linfoma, refuerza la necesidad de estudios para entender su curso y mejorar protocolos terapéuticos que incrementen tanto la sobrevida como la calidad de vida para estos pacientes

Histomorphological and immunophenotypic diagnoses of gastrointestinal stromal tumors and other sarcomas that affect the intestine of dogs

In view of the morphological similarity between gastrointestinal stromal tumors (GIST) and other sarcomas of the intestine of dogs, the aim was to carry out the histomorphological and immunohistochemical diagnosis of these tumors, associating breed, sex and age, location and tumor invasion. 217 cases were evaluated by histopathology and 36 diagnosed by immunohistochemistry were included (24 GIST and 12 other intestinal sarcomas). Mixed breed dogs were the most diagnosed with GIST, mainly elderly females (9.5±2.2 years); in the other intestinal sarcomas, crossbreeds and Dachshunds, males and females, were equally affected. The cecum was the most affected by GISTs, with tumor invasion of the intestinal layers in all cases. The small intestine was the most affected by the other intestinal sarcomas, with invasion of the layers in most of these tumors. GISTs expressed markers such as CD117 and DOG-1, unlike other intestinal sarcomas. GIST and other intestinal sarcomas denoted histomorphological and immunophenotypic characteristics similar to histopathology, justifying the association of immunohistochemistry for the definitive diagnosis. Keywords: CD117; DOG-1; GIST; veterinary oncolog

Diagnosis, Prognosis and Treatment of Canine Cutaneous and Subcutaneous Mast Cell Tumors

Mast cell tumors (MCTs) are hematopoietic neoplasms composed of mast cells. It is highly common in dogs and is extremely important in the veterinary oncology field. It represents the third most common tumor subtype, and is the most common malignant skin tumor in dogs, corresponding to 11% of skin cancer cases. The objective of this critical review was to present the report of the 2nd Consensus meeting on the Diagnosis, Prognosis, and Treatment of Canine Cutaneous and Subcutaneous Mast Cell Tumors, which was organized by the Brazilian Association of Veterinary Oncology (ABROVET) in August 2021. The most recent information on cutaneous and subcutaneous mast cell tumors in dogs is presented and discussed

Hematological and biochemical profiles of canine CD45− T lymphomas are different from other immunophenotypes

Background: Canine multicentric lymphomas are lymphoproliferative malignancies that have increased in recent decades. The patient’s treatment and prognosis are determined by the grade, histological type, and lymphoma immunophenotyping. Aim: To investigate the paraclinical signs and survival time in canines with different lymphoma immunophenotypes. Methods: Over 2 and a half years, 47 untreated dogs were diagnosed with multicentric lymphoma at the Veterinary School Hospital of Uruguay. The disease was clinically and cytologically diagnosed, and immunophenotyping was determined by flow cytometry. After the immunophenotyping, most of the patients were grouped into the following: B (LB), T aggressive (LTCD45+), or T-zone lymphoma (LTCD45−). The patients’ haematological values, calcemia, lactate dehydrogenase (LDH) levels, and plasmatic electrophoretic profiles were all determined immediately after that. Results: Of all canine lymphomas, 55.3% were B, 31.9% were LTCD45+, and 10.6% were TCD45−. Only 2.2% were classified as nonB/nonT, and survival time differed between groups. Patients with LTCD45−lymphomas had a mean life span of 641 days after diagnosis, followed by LB (166 days) and LTCD45+(62 days). Red blood cell count, hematocrit, and hemoglobin levels did not differ between groups. However, the LTCD45− group had significantly higher lymphocyte levels than the LTCD45+ and LB groups (p = 0.01 and 0.006, respectively). Levels of albumin, alpha-1, and alpha-2 globulins did not differ between groups. On the other hand, gamma globulins levels in the LTCD45− were higher than in the other lymphoma groups. The presence of hypercalcemia and high plasma LDH levels were associated with patient severity. Only the TCD45+ group had hypercalcemia although both the LB and TCD45+ groups had elevations in LDH activity. Interestingly, there was a direct relationship between high LDH values (greater than 500 IU/l) and lower survival in TCD45+ lymphomas. Conclusion: Survival time and hematological and biochemical patterns differed among canine lymphomas immunophenotypes. Patients of LTCD45− phenotype showed higher lymphocyte counts and gamma globulin levels and more prolonged survival. Serum LDH activity may provide additional prognostic information in high-grade T-cell lymphoma

Immunohistochemical Expression of Human Epidermal Growth Factor Receptor 2 and Ki67 in Apocrine Gland Anal Sac Adenocarcinoma

Apocrine gland anal sac adenocarcinoma is an aggressive neoplasm, and surgery remains the treatment of choice, although it is controversial in advanced cases. The prognostic factors are not well established. Human Epidermal Growth Factor Receptor 2 (HER2) is a membrane protein related to tumorigenesis, whereas Ki67 is a nuclear protein related to cell proliferation. Both are potential prognostic markers and therapeutic targets. This study aimed to evaluate the expression of HER2 and Ki67 markers in canine apocrine gland anal sac adenocarcinoma. The tumor samples were divided into four groups: largest tumor diameter less than 2.5 cm, largest tumor diameter greater than 2.5 cm, metastatic lymph nodes, and control group of non-neoplastic anal sacs. Each contained 10 samples. Immunohistochemistry was performed to verify the expression of HER2 and Ki67 markers. Positive HER2 staining was observed in 45% of the neoplastic cases and negative HER2 staining in 100% of the control group. The Ki67 expression had a median of 25% in all groups, except for the control group, which had a median of 8%. The HER2 and Ki67 expression was present in apocrine gland anal sac adenocarcinoma, making them potential therapeutic targets. However, it was not possible to determine the clinical value of either marker