Lung lobe torsion in association with a pulmonary papillary carcinoma in a dog.

Lung lobe torsion (LLT) is an uncommon condition in dogs reported to be most commonly idiopathic or secondary to trauma, pleural effusion, lung lobectomy or thoracic neoplasia. Carcinomas are the most common primary lung tumours in dogs, but only a few cases have been reported in association with LLT in veterinary medicine. This case describes an adult male neutered Labrador, which presented with lethargy, weight loss and pleural effusion. Computed tomography (CT), cytology of the lung, thoracocentesis and fluid analysis were performed. CT revealed pleural effusion and torsion of the left cranial lung lobe with no evidence of a pulmonary mass or metastatic disease. Thoracotomy and left cranial lung lobectomy were performed. Intraoperatively there was no macroscopic evidence of pulmonary neoplasia. Histopathology of the lobar tissue confirmed grade 2 pulmonary papillary carcinoma. It is possible that early detection and surgical management might help to prevent the morbidity and mortality associated with LLT. However, as in this case, the underlying cause for the LLT will ultimately determine the patient's prognosis. The final diagnosis of papillary carcinoma in this case, was only made via histopathological assessment of the pulmonary tissue as it was unclear on the advanced imaging and macroscopic intraoperative evaluation of the lungs. This case highlights the importance of considering pulmonary neoplasia as a differential for LLT even in the absence of a macroscopic mass, and therefore the value of performing histopathology on the excised lung tissue.

Haematologic toxicity in dogs with mast cell tumours treated with vinblastine/prednisolone chemotherapy with/without radiotherapy.

OBJECTIVES: To determine whether dogs with surgically excised mast cell tumours receiving a vinblastine/prednisolone chemotherapy protocol in combination with radiation therapy are at greater risk of myelosuppression than patients receiving the chemotherapy protocol alone. MATERIALS AND METHODS: Retrospective study of clinical records of dogs with mast cell tumours that, subsequent to surgical excision, had received combination vinblasine/prednisolone chemotherapy. Dogs were assigned to two groups: those treated with adjunctive radiotherapy and vinblastine/prednisolone (RT group) and those treated with surgery followed by vinblastine/prednisolone alone (control group). Haematology results were compared between groups. RESULTS: Forty-three cases and 43 controls of similar breed, age and bodyweight were included. Concurrent radiation and vinblastine chemotherapy did not appear to increase the risk of neutropenia, which was observed in 18.6 and 23.2% of cases in the RT and control groups, respectively. CLINICAL SIGNIFICANCE: Radiation and vinblastine chemotherapy can be safely combined in dogs with mast cell tumours without increasing the risk of clinically important myelosuppression.

Expression of VEGFR and PDGFR-α/-ß in 187 canine nasal carcinomas.

Radiotherapy represents the standard of care for intranasal carcinomas. Responses to tyrosine kinase inhibitors (TKIs) have been reported but data on expression of target receptor tyrosine kinases (rTKs) is limited. This study characterizes the expression of vascular endothelial growth factor receptor (VEGFR), platelet-derived growth factor receptor (PDGFR)-α and PDGFR-ß in canine intranasal carcinomas. Histological samples from 187 dogs were retrieved. Immunohistochemistry was performed using commercially available antibodies. Expression of rTKs was classified into weak, moderate or intense and additionally recorded as cytoplasmic, membranous, cytoplasmic-membranous, nuclear or stromal. VEGFR was expressed in 158 dogs with predominantly moderate expression (36.9%) and a cytoplasmic-membranous expression pattern (70.9%). PDGFR-α was detected in 133 with predominantly weak expression (57.9%) and cytoplasmic pattern (87.9%). PDGFR-ß was identified in 74 patients with a predominantly moderate expression (17.6%) and cytoplasmic expression pattern (63.5%). Co-expression of rTKs was common. These results confirm expression of VEGFR, PDGFR-α and PDGFR-ß in canine intranasal carcinomas and support the utility of TKIs.