Orthostatic hypotension secondary to a suspected thymoma in a dog: A case report

This is the first case report description, to our knowledge, of a cranial mediastinal mass (suspected thymoma) causing orthostatic hypotension in a dog. A Labrador Retriever presented for urethral stent placement during cystoscopy secondary to transitional cell carcinoma diagnosis. During anesthesia, the patient had unexpected severe and poorly-responsive hypotension following a shift in position.