Goiter Introduction

• The term goiter refers to:

• An abnormal growth of the thyroid gland

• Goiters can be:

• Diffuse or nodular:

• Depending on the etiology

• May be associated with:

• Normal, decreased, or increased thyroid hormone production

• The clinical manifestations vary with:

• Thyroid function and with the size and location of the goiter

• Anatomical Relationships:

• In healthy adults without iodine deficiency:

• A normal thyroid gland is approximately:

• 4.0 cm to 4.8 cm x 1.0 cm to 1.8cm x 0.8 cm to 1.6 cm in size

• Mean sonographic volume of:

• 7 mL to 10 mL:

• Thyroid volume measured by ultrasonography:

• Is slightly greater in men than women

• Increases with age and body weight

• Decreases with increasing iodine intake

• Weight of:

• 10 grams to 20 grams

• The normal thyroid gland:

• Is immediately caudal to the larynx and encircles the anterolateral portion of the trachea

• The thyroid gland is bordered by:

• The trachea and esophagus posteriorly

• The carotid sheath laterally

• Enlarging thyroid lobes:

• Usually grow outward:

• Because of their location in the anterior neck in front of the trachea:

• Covered only by thin strap muscles, subcutaneous tissue, and skin

• As a result of this outward growth:

• Even very large goiters may not compress the trachea or impinge on the great vessels lateral to the lobes:”

• However, in patients with substantial enlargement of one lobe or asymmetric enlargement of both lobes:

• The trachea, esophagus, or blood vessels:

• May be displaced or, less often, compressed

• Bilateral lobar enlargement:

• Especially if the goiter extends posterior to the trachea:

• May cause either:

• Compression or concentric narrowing of the trachea

• Compression of the esophagus

• Compression of the jugular veins

• The thoracic inlet:

• Is an ovoid area that measures approximately 5 cm x 10 cm:

• Boundaries:

• The sternum anteriorly

• The first thoracic vertebral body posteriorly

• The first ribs laterally

• The inlet is traversed by the:

• Trachea

• Esophagus

• Blood vessels

• Nerves

• The inferior pole of each thyroid lobe:

• Normally lies above the thoracic inlet:

• However, with some goiters, there is growth of one or both lobes through the inlet into the thoracic cavity:

• Which can result in obstruction of any of the structures in the inlet:

• Such goiters are called substernal:

• Although retrosternal is probably a more precise term

• Most substernal goiters are in the:

• Anterolateral mediastinum

• But approximately 10%:

• Are located primarily in the posterior mediastinum

• The prevalence of substernal goiter as a percentage of thyroidectomies:

• Ranges from 2% to 19%

#Arrangoiz #ThyroidSurgeon