Surgical excision of ectopic thyroid carcinoma involving the base of the tongue in dogs: three cases (1980-1987).

Localized thyroid carcinoma involving the base of the tongue was diagnosed in 3 dogs examined because of a midline cervical mass rostroventral to the larynx. These masses had been present for 4 to 12 months and were firm, nonsensitive, and fixed in position. One dog had progressive dysphagia and dyspnea. Masses were surgically excised together with the base of the tongue and portions of the hyoid apparatus. Severe dyspnea that developed immediately after surgery in 1 dog was managed by tracheostomy intubation for 4 days. Transient dysphagia developed in all dogs. Hydration was maintained by IV fluid administration until water and food of gruel consistency could be swallowed 1 to 6 days after surgery. Consistency of food was gradually thickened to normal, as swallowing improved 6 days to 2 months after surgery. One dog developed aspiration pneumonia that resolved after antimicrobial administration and improved swallowing that prevented further aspiration. After 9 months, 3 years, and 6 years, the dogs were clinically normal.