Abstract
BACKGROUND: Patients rarely develop complicated infections in thyroid cysts. Here, we describe a patient with chronic infected unilateral giant thyroid cyst related to diabetes mellitus (DM). CASE SUMMARY: A 66-year-old male was admitted due to an evident neck lump for 5 d after approximately 40 years of gradually progressive neck mass and 7 years of DM. Doppler ultrasound and computed tomography scan showed a giant lump in the left thyroid gland lobe. He was diagnosed with a large thyroid nodule complicated by tracheal dislocation and had surgical indications. Surgical exploration revealed evident inflammatory edema and exudation between the left anterior neck muscles, the nodule and glandular tissue. Fortunately, inflammatory lesions did not affect major neck vessels. Finally, a left partial thyroidectomy was performed. Macroscopic observation showed that the cystic thyroid mass consisted of extensive cystic wall calcification and was rich in massive rough sand-like calculi content and purulent matter. Postoperative pathology confirmed benign thyroid cyst with chronic infection. CONCLUSION: The progression of this chronic infectious unilateral giant thyroid cyst may have been related to DM, and identifying blood vessels involvement can prevent serious complications during operation.