Complete excision of the basihyoid bone in two dogs during surgical treatment of ectopic thyroid carcinoma

Abstract Two dogs were presented to our institution for further investigations of a mass lesion in the cranioventral cervical region. Computed tomography revealed both masses to be in the region of the hyoid apparatus, and partial lysis of the basihyoid bone was noted in both cases. Surgical removal of each mass, along with complete excision of the basihyoid bone, was performed. Histopathology was consistent with a thyroid follicular carcinoma for Patient A and a compact type thyroid carcinoma for Patient B. Prehension of food, mastication, water intake and vocalisation were unaffected immediately after surgery and at follow‐up (3.5 years and 7 months, respectively). Both dogs received courses of adjuvant single agent chemotherapy. Patient A was euthanased 3.5 years after surgery due to owner‐perceived poor quality of life and, at the time of writing this report 7 months after surgery, Patient B had finished chemotherapy without gross evidence of disease recurrence.