A 59-year-old man developed an 11-centimeter thyroglossal duct cyst extending down to his aortic arch, mimicking a parathyroid condition before doctors successfully removed it through a cervical incision, Cureus reported.
The rare mediastinal mass caused hoarseness, shortness of breath, and left vocal fold immobility after symptoms began in February 2020.
Computed tomography scans performed in June 2020 revealed a water-density cyst inseparable from the left thyroid lobe that compressed the trachea and displaced it to the right. Fine-needle aspiration yielded clear, colorless fluid without a clear cytological diagnosis, leading physicians to initially suspect a parathyroid cyst.
Surgeons operated under general anesthesia in August 2020 using a Kocher collar incision with thoracic surgical backup available. After dissecting the left recurrent laryngeal nerve, they delivered the mass intact from the superior mediastinum and divided a thin pedicle connecting it to the left thyroid lobe.
Histological examination later showed an inflamed, sclerotic cyst wall with adjacent thyroid parenchyma, confirming the lesion was a thyroglossal duct cyst. The patient experienced an uneventful recovery and left the hospital on postoperative day 2.
During a follow-up examination in May 2025, the patient remained well and had fully recovered his left vocal fold function. Postoperative imaging was unavailable because the patient declined further computed tomography scans, leaving the radiological absence of recurrence unestablished.
Thyroglossal duct cysts represent the most common congenital neck anomalies, typically presenting near the hyoid bone during childhood. Mediastinal extensions remain exceptional and frequently complicate diagnoses by mimicking thymic, bronchogenic, or lymphatic cysts.
The 59-year-old man experienced hoarseness and shortness of breath starting in February 2020, along with left vocal fold immobility.
* Why did doctors initially misdiagnose the mass? The lower-neck location, mediastinal extension, and water-clear fluid obtained from fine-needle aspiration led to a working diagnosis of a non-functioning parathyroid cyst.
* How was the giant cyst removed?
Surgeons removed the lesion intact through a standard cervical collar incision after carefully dissecting the left recurrent laryngeal nerve and using upward traction with blunt digital dissection.
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