Patient presented for further evaluation of acute onset of lethargy, inappetance that began 24 hours earlier, and a sudden onset of ventral neck swelling. The patient was anemic and mildly azotemic on presentation with pleural effusion confirmed as hemothorax. A CT examination (pre and post IV contrast) of the cervicothoracic region was performed with the patient in dorsal recumbency.
Pertinent findings:- A heterogenous mass is centered at the level of the left lobe of the thyroid gland. A normal left lobe of the thyroid gland is not identified and the right lobe is normal.- The cranial margin of this mass is convex and well defined and the mass extends nearly the entire length of the cervical region with a poorly defined caudal margin.- There is a large volume of soft tissue material bordering the ventral margin of the trachea that is non-contrast enhancing.- There is a moderate volume of mediastinal fluid and a large volume of gravity dependent pleural fluid (consistent with the reported hemothorax).
Conclusion: A primary left thyroid neoplastic mass such as thyroid carcinoma is primarily suspected and a rupture of this mass resulting in cervical, mediastinal and pleural hemorrhage is primarily suspected. A case with a very similar disease process has been previously reported (Slensky KA, Volk SW, Schwarz T, Duda L, Mauldin EA, Silverstein D. Acute severe hemorrhage secondary to arterial invasion in a dog with thyroid carcinoma. J Am Vet Med Assoc. 2003 Sep 1;223(5):649-53, 636.)