Thymus Tumor In Dog. Thymomas are rare tumors in both cats and dogs and they are associated with myasthenia gravis. Common clinical signs include coughing and changes to a pet’s breathing rate and/or effort.

A paraneoplastic syndrome of myasthenia gravis, nonthymic malignant tumors, and/or polymyositis occurs in a significant. The primary tumor, a malignant thymoma, filled the cranial mediastinum and had invaded the cranial vena cava. Pneumonitis and pericarditis + chemotherapy