This week’s case is a 17-year-old male Siamese cat with history of vomiting, diarrhea, and weight loss. It is an interesting presentation. What are your differentials?
There is a large, oval soft tissue opacity mass in the cranial mediastinum. This is seen cranial to the cardiac silhouette on lateral projections, and superimposed on the spine on the ventrodorsal projections. There are nodules superimposed over the cardiac silhouette on the lateral projections. There is also a diffuse bronchial pattern. Within the abdomen, the small intestinal loops are mildly enlarged.
- Round cell neoplasia (lymphoma, mast cell tumor) with possible GI involvement
- Mediastinal cyst
- Ectopic thyroid tissue
The nodules are unusual for lymphoma and may also represent metastatic disease from other neoplasia, or bronchial secretions. The bronchial pattern is consistent with lower airway disease.
High grade lymphoma with small intestinal and liver involvement. The pulmonary nodules resolved with chemotherapy however the mediastinal mass remained visible over the next four months of treatment.