Thyroid gland

From Cat
1. Normal Thyroid Gland, 2. Parathyroid gland, 3. Parathyroid Gland, 4. Enlarged Thyroid Gland

The feline thyroid gland is a single bilobar gland located in the neck region of cats, ventral to the trachea between the larynx and xiphoid process[1].

The two lobes of the thymus do not interconnect. Small amounts of ectopic thyroid tissue may be scattered throughout the ventral neck and mediastinum. The normal thyroid gland cannot be palpated in healthy cats and can be difficult to locate at exploratory surgery.

The parathyroid gland is situated intimately anterior to the thyroid gland.

Enlarged thyroid gland is seen in association with hyperthyroidism.

The function of the thyroid is to;

  1. regulate metabolic function, via production of thyroxine (T4) and thriiodothyronine (T3). These biologically active hormones require the dietary uptake of iodine for activation.
  2. regulate calcium by follicular cell secretion of calcitonin

Most disease changes to the thyroid represent benign adenomatous hyperplasia, but thyroid carcinoma and dermoid cysts have been reported in cats[2].


  1. Olson, JK (2001) Hyperthyroidism. In Lappin, MR (ed) Feline internal medicine secrets. Hanley & Belfus, Philadelphia. pp:259
  2. Tolbert K et al (2009) Dermoid cysts presenting as enlarged thyroid glands in a cat. J Feline Med Surg 11(8):717-719