Intrathoracic goiter refers to simple goiter and thyroid tumor in the retrosternum or mediastinum, accounting for 9% to 15% of thyroid diseases and 5.3% of mediastinal tumors. There are more females than males, the ratio of male to female is 1:3 to 4, and the majority are over 40 years old. Patients are often accompanied by different degrees of hunchback, thick and short neck, obesity, and some patients have a history of thyroid surgery. Asymptomatic people account for about 30%. The main clinical manifestation is caused by the compression of the mass on the surrounding organs. If the compression of the trachea causes difficulty in breathing and wheezing; the compression of the superior vena cava causes the superficial veins of the upper chest and neck to become enraged, and the upper limbs become edematous, such as superior vena cava syndrome; the compression of the esophagus causes difficulty in swallowing; the esophagus is softer than the trachea, and the esophagus can still avoid the pressure of the tumor even if the esophagus is pressurized or displaced, the above symptoms seldom appear. The severity of symptoms is related to the size and location of the mass. When the intrathoracic goiter simply increases in size, the compression symptoms will appear. With the narrowing of the retrosternal space, the tumor may show symptoms at an early stage even if it is not big. In individual patients, acute dyspnea is caused by the mass embedded in the thoracic inlet or spontaneous or traumatic hemorrhage. In severe cases, long-term compression of the trachea by the tumor leads to tenderness or even a sense of suffocation, and these symptoms may be aggravated when lying on the back or moving the head to the affected side. If there is hoarseness and loss of voice, it is often caused by malignant tumor compressing the recurrent laryngeal nerve; benign intrathoracic goiter compressing the recurrent laryngeal nerve is rare; Horner’s syndrome is caused by the tumor descending to the posterior mediastinum and compressing the sympathetic nerve, which is not common. If accompanied by panic, shortness of breath, night sweats, hypertension, etc., it suggests hyperthyroidism. Intrathoracic goiter may be partially or completely located in the thoracic cavity, and is divided into two categories according to its source of generation: 1. Posterior sternal goiter Located in the anterior mediastinum, it has a direct connection with the cervical thyroid gland, and is also known as secondary posterior sternal goiter. Its blood supply is mainly derived from the inferior thyroid artery and its branches. 2.True intrathoracic goiter Most of them are located in the visceral mediastinum. After entering the thoracic cavity, it is located in the inner and posterior part of the large blood vessels and close to the trachea. Such intrathoracic goiter is connected to the cervical thyroid only with blood vessels and fibrous cords or without any connection. Their blood supply originates from intrathoracic blood vessels, which is less common. Physical examination: An infiltrative intrathoracic goiter may have an enlarged thyroid gland palpable in the neck and extending into the chest, with the lower pole not being palpable. In patients with a history of previous thyroid surgery and complete retrosternal goiter, it is difficult to palpate the mass in the neck. Physical examination should differentiate between the relationship of the thyroid gland in the neck and the intrathoracic thyroid, the relationship of the mass to swallowing activity as well as the palpation of the lower border and the extension of the thyroid tumor into the intrathorax.