Synovial myxosarcoma in the scapulohumeral joint of a dog: a case report.

A 12-year-old, 3 kg spayed female mixed-breed dog was evaluated to assess a 1-year history of intermittent right forelimb lameness that did not have adequate response to nonsteroidal anti-inflammatory drugs. The radiographic study performed under sedation showed multifocal radiolucent areas affecting both the right humerus and scapula with focal soft tissue swelling; a CT scan confirmed the existence of an aggressive and invasive soft tissue mass affecting the scapulohumeral joint. Fine needle aspiration results suggested a low-grade synovial sarcoma and therefore a scapulectomy was performed. The biopsy showed spindle to stellated cells immersed in a basophilic and mucinous (myxoid) matrix with mild to moderate anisocytosis, moderate anisokaryosis, some binucleated cells and sporadic multinucleated cells. These findings are consistent with low-grade synovial myxosarcoma, a not well described synovial neoplasm that can mimic other commonly seen joint tumors or even septic arthritis on radiographs. The purpose of this case report is to describe the first reported synovial myxosarcoma affecting the scapulohumeral joint of a small dog.

Pancreatic adenocarcinoma treated with surgical resection, toceranib phosphate and firocoxib in a dog: a case report.

Exocrine pancreatic carcinomas are rarely reported in dogs. A ductal pancreatic adenocarcinoma in a 10-year-old intact beagle is described in this report. The diagnosis was made based on clinical signs, imaging (abdominal ultrasound and CT scan) and histopathology. Treatment consisted of partial right lobe pancreatectomy followed by adjuvant therapy with toceranib phosphate (Palladia®) and firocoxib (Previcox®) for six months. The treatment was well tolerated, and the survival time was 445 days. To our knowledge, this is the longest survival reported in the literature for a dog diagnosed with exocrine pancreatic adenocarcinoma. The results described here may contribute to provide a better understanding about this neoplasia and potential treatment options.

Conjunctival squamous cell carcinoma in a reindeer (Rangifer tarandus tarandus).

An 8-year-old female adult reindeer (Rangifer tarandus tarandus) was referred to the Veterinary Hospital of Madrid for evaluation of a conjunctival mass on the left eye which had been present for about 2 months. A surgical excision was performed and biopsy material submitted for light microscopic evaluation which confirmed the diagnosis of conjuctival squamous cell carcinoma. Nuclear p53 immunolabeling was found in 52% of the neoplastic cells. Follow-up examination at 12 months postsurgery did not reveal recurrence of this neoplasm. Conjunctival squamous cell carcinoma has not been reported previously in reindeer and seems to have similar characteristics to the one existing in bovine species.

Role of Leishmania infantum in Meningoencephalitis of Unknown Origin in Dogs from a Canine Leishmaniosis Endemic Area.

The main hypothesis for the aetiology of meningoencephalitis of unknown origin (MUO) in dogs is an autoimmune or genetic cause that is associated with a triggering event (environmental factors/infectious agents). The aim of this ambispective cohort study was to test for Leishmania infantum infection in the blood and cerebrospinal fluid (CSF) of dogs with MUO in an endemic area of canine leishmaniosis. Dogs with MUO were selected amongst all dogs undergoing blood anti-L. infantum antibody testing (control group). The blood plasma or serum samples from all dogs were analysed for anti- L. infantum antibodies by a quantitative indirect fluorescent assay (IFAT). In dogs with MUO, CSF samples were obtained for analysed by PCR detection of L. infantum DNA. Forty-four percent and 22% of the dogs in the MUO group featured magnetic resonance imaging (MRI) findings and CSF cytology respectively, consistent with L. infantum infection. IFAT, PCR, and histological findings were negative for L. infantum. A significant difference in L. infantum infection prevalence was found between the control and MUO group (p = 0.0022). While it seems unlikely that L. infantum plays a role in the aetiology of MUO, in endemic areas, this pathogen should be included in the differential diagnosis of this neurological disorder.

Cyclin D1 immunohistochemical expression and somatic mutations in canine oral melanoma.

Canine oral melanoma (COM) is the most frequent tumour with oral localization in dogs. Copy number gains and amplifications of CCND1, a gene coding for Cyclin D1, are the most frequent chromosomal aberrations described in human non-UV induced melanomas. Twenty-eight cases of COM were retrieved from paraffin-blocks archives. A total of 4 µm thick sections were immunostained with an antibody against human Cyclin D1 and Ki-67. Cyclin D1 and Ki-67 expressions were scored through two counting methods. DNA was extracted from 20 µm thick sections of formalin-fixed paraffin-embedded blocks. Pathological and surrounding healthy tissue was extracted independently. Cyclin D1 immunolabelling was detected in 69% (18/26) while Ki-67 was present in 88.5% (23/26) of cases. Statistical analysis revealed correlation between two counting methods for Cyclin D1 (r = 0.54; P = .004) and Ki-67 (r = 0.56; P = .003). The correlation found between Ki-67 and Cyclin D1 indexes in 16/26 cases labelled by both antibodies (r = 0.7947; P = .0002) suggests a possible use of Cyclin D1 index as prognostic marker. Polymerase chain reaction analysis on CCND1 coding sequence revealed the presence of nine somatic mutations in seven samples producing synonymous, missense and stop codons. Since none of the single-nucleotide polymorphisms was found to be recurrent, it is suggested that overexpression of Cyclin D1 may be the consequence of alterations of CCND1 upstream regions or other genetic aberrations not detectable with the methodology used in this study. Future studies are needed to verify the potential use of Cyclin D1 index as prognostic indicator and to highlight the molecular events responsible for Cyclin D1 overexpression in COMs.

Diagnostic accuracy of electrocardiographic P wave related parameters in the assessment of left atrial size in dogs with degenerative mitral valve disease.

The purpose of this research was to compare the accuracy of newly described P wave-related parameters (P wave area, Macruz index and mean electrical axis) with classical P wave-related parameters (voltage and duration of P wave) for the assessment of left atrial (LA) size in dogs with degenerative mitral valve disease. One hundred forty-six dogs (37 healthy control dogs and 109 dogs with degenerative mitral valve disease) were prospectively studied. Two-dimensional echocardiography examinations and a 6-lead ECG were performed prospectively in all dogs. Echocardiography parameters, including determination of the ratios LA diameter/aortic root diameter and LA area/aortic root area, were compared to P wave-related parameters: P wave area, Macruz index, mean electrical axis voltage and duration of P wave. The results showed that P wave-related parameters (classical and newly described) had low sensitivity (range=52.3 to 77%; median=60%) and low to moderate specificity (range=47.2 to 82.5%; median 56.3%) for the prediction of left atrial enlargement. The areas under the curve of P wave-related parameters were moderate to low due to poor sensitivity. In conclusion, newly P wave-related parameters do not increase the diagnostic capacity of ECG as a predictor of left atrial enlargement in dogs with degenerative mitral valve disease.

Evaluation of low-dose metronomic (LDM) cyclophosphamide toxicity in cats with malignant neoplasia.

Oral administration of low-dose cyclophosphamide in pets with spontaneously occurring malignant neoplasms has become a common practice in veterinary medicine. The purpose of this retrospective study was to investigate toxicity events in cats with spontaneous malignancies receiving cyclophosphamide as a metronomic therapy for at least 1 month. The number and severity of clinical, haematological and biochemical adverse events were recorded according to the Veterinary Cooperative Oncology Group's Common Terminology Criteria for Adverse Events v1.1 classification scheme. Twenty-four cats were enrolled in the study with a total number of 27 neoplasms: 13 sarcomas, 12 carcinomas, one melanoma and one neuroendocrine tumour. Seventeen cats presented with macroscopic disease, while seven had microscopic disease. Seven cats (29%) had metastasis either to the regional lymph nodes and/or distant sites at the time of study enrolment. Additional medications, administered concurrently, included non-steroidal anti-inflammatory drugs (17), toceranib (4) and thalidomide (7). Four cats showed grade I gastrointestinal toxicity during the first month of treatment, which was controlled with antiemetics. Overall, 2/24 cats (8%) showed grade I haematological toxicities and 1/24 (4%) showed grade I renal toxicity in the first 4 weeks. Median follow-up for all cats was 30 days (range 30-360 days). For the 15 cats with follow-up longer than 1 month the only additional toxicities observed were two grade III and one grade II azotaemia that occurred after 2 months of therapy. Low-dose cyclophosphamide seems to be a well-tolerated option for cats bearing primary or metastatic tumours. Evaluation of toxicity after long-term administration is still needed.