+ General Considerations
- Thymic LSA is the most common thymic tumor in cats
- Thymic LSA is less circumscribed than thymoma with local extension through the thoracic inlet, around the heart base or into the lungs, pericardium, or intercostal or cervical musculature
+ Clinical Features
- Mean age 4.1 years
- Breed predisposition: Siamese
- FeLV reported in 50%-80% of thymic LSA
- Histopathologic features: neoplastic lymphocytes ranging from well-differentiated small lymphocytes to lymphoblastic and histiocytic forms
- Lymphoblastic LSA is the most common for accounting for 58% (11/19) cases
- Mediastinal LSA invading cranial vena cava (with thrombosis and cranial vena cava syndrome) has been reported
+ Diagnosis
- Thoracocentesis or FNA: lymphoblasts rather than mature lymphocytes seen with thymoma
- Ultrasonography: homogenous and hypoechoic compared to mixed echogenicity with thymoma
+ Treatment
- Chemotherapy
- ± Radiation Therapy