Imagistic and cytological diagnosis in a case of mediastinal mesenchimal neoplasia in dog.

This paper presents the case of a female dog with a mediastinal mass. Clinical, imagistic and cytological evaluation of the patient are presented. A 4 years old female Rottweiler was referred to FMV Iasi Clinics with signs of respiratory distress resistent to treatment. Clinical examination of the dog revealed paroxostic, productive cough, harsh respiratory sounds, fever and regurgitation. Radiographs of the spine and thorax in right and left lateral and dorso-ventral incidence revealed a large mass occupying the cranial mediastinum and left cranial thorax, pushing the heart and the carina caudally and the esophagus and the trachea laterally, to the right. The esophagus was dilated cranially due to external mass compression and aspiration pneumonia signs were found in the lung. Small nodular mases were also seen in all the lung lobes. Endoscopy of the esophagus and trachea revealed the integrity of these organs and external compression. Ultrasound examination showed an hperechoic heterogenous mass. Ultrasound-guided fine-needle aspiration of the mass was performed. The cytological examination of the samples showed necrosis and a pleomorphic cell population with obvious malignancy criterias: macrocytosis, anisocytosis, anisocaryosis, multiple nucleoli, numerous mytosis, high N/C ratio. The pleomorphic aspect of the mesenchymal cell population prevented a clear classification of the tumour but revealed a high malignancy mesenchymal mediastinal neoplasia. The differential was made between extra-skeletal osteosarcoma/chondrosarcoma, hemangiopericitoma and fibrosarcoma.