Society of Veterinary Nuclear Medicine

11-year-old castrated male Domestic Short Hair

Polyuria, polydypsia and weight loss.

Physical examination

  • Thin, no palpable thyroid.


  • Elevated total T4 and free T4.

Scintigraphy scan.

CT 3D reconstruction fused with the scintigraphy scan.

  • Absent ventral cervical radionuclide uptake.
  • Focal increase in radionuclide uptake ventral laryngeal region on midline.

Hyperthyroidism secondary to ectopic sublingual thyroid adenoma.

The patient was treated and became euthyroid. He began to gain weight and had resolution of his polyuria and polydypsia.

The foramen caecum, is a small pouch that forms on the floor of the embryonic pharynx and represents the location of the origin of the epithelial proliferation that becomes the thyroid. The migration path of the thyroid from its embryologic origin in the pharynx along the thyroglossal duct normally ends in the cranial cervical region. Note the close proximity of the thyroglossal duct to the basihyoid bone. Ectopic lingual thyroid may appear as a mass in the dorsum of the tongue. Sublingual ectopic thyroid presents in a midline position cranial (suprahyoid), caudal (infrahyoid), or at the level of the hyoid bone.

Thyroid embryology.

Thyroid embryology.

  • De Felice M & Lauro R. Thyroid development and its disorders: genetics and molecular mechanisms. Endocrine Reviews 2004 25 722–746.
  • Peterson M.E. and Broome M.R. Thyroid Scintigraphy Findings in 1,572 Cats with Hyperthyroidism. in Conference Proceedings ECVIM. 2012. Maastricht, Netherlands.
  • Patnaik A.K., Peterson M.E. and Hidgon A., Ectopic Lingual Thyroid Tissue in a Cat. J Feline Med Surg, 2000. 2(3): p. 143-6.
  • Reed T.P., Brisson B.A. and Schutt L.K., Cystic Ectopic Lingual Thyroid Tissue in a Male Cat. J Am Vet Med Assoc, 2011. 239(7): p. 981-4.
  • Peterson M.E. and Broome M.R., Radioiodine for Feline Hyperthyroidism, in Current Veterinary Therapy XIV, J.D. Bonagura and D. Twedt, Editors. 2012: Philadelphia