Swollen thyroid gland. Coloured coronal magnetic resonance imaging (MRI) scan of the neck and chest of a 49-year-old patient with a swollen thyroid gland (pink). This frontal view also shows the lungs (centre left and centre right), the heart (lower left), the shoulders, the upper abdomen, and the throat. A swollen thyroid gland is also known as a goitre. The condition is usually due to a deficiency of iodine, but may also be due to thyroiditis (an autoimmune disease) or cancer. Here, the swollen gland is causing breathing and swallowing difficulties for the patient. Treatment is with iodine supplements or surgical removal of the gland.