Abstract:

The author of this paper repored the diagnostic and treatment process of one patient with secondary primary tracheal adenoid cystic carcinoma（TACC）. From the perspective of disease occurrence， the patient was successively diagnosed with tracheal basal cell adenocarcinoma and tracheal adenoid cystic carcinoma， which was extremely rare in clinical practice， providing a reference for studying the correlation and differences in the incidence of different types of tracheal cancer. At the same time， during the treatment process， massive bleeding from the tracheostomy site occurred during radiotherapy， deepening the understanding of radiotherapy complications in TACC. The patient， a 61-year-old female， underwent surgical treatment for tracheal basal cell adenocarcinoma five years ago. One year ago， the patient experienced exertional dyspnea， which gradually worsened， severely affecting her daily life， leading to her hospital admission for further diagnosis and treatment. The physical examination results showed a 2 cm×1 cm irregular mass in the right neck， with normal skin temperature and color， no tenderness or pain on pressure， and good mobility. Enhanced computed tomography（CT） of the larynx indicated cauliflower-like soft tissue masses on the right and posterior walls of the trachea and a nodule on the anterior margin of the sternocleidomastoid muscle in the right supraclavicular region， suggesting recurrence of an intratracheal tumor.The differential diagnosis included tracheal squamous cell carcinoma， which often forms keratin pearls and exhibits more significant cellular atypia. The immunohistochemical markers are also different， and the results of pathology and immunohistochemistry examinations can effectively distinguish them. The patient underwent resection of the mass along with the tracheal wall and excision of the right supraclavicular mass. The postoperative pathology confirmed adenoid cystic carcinoma of the trachea with local neural involvement. Given the patient’s symptoms of tracheal obstruction and the possibility of cervical lymph node metastasis of TACC， surgery was the primary treatment choice. Postoperative radiotherapy further controlled residual tumor cells， reduced the risk of recurrence， and improved the local control rates. After 12 months of follow-up post-radiotherapy， no signs of tumor recurrence were observed. The clinicians should reinforce diagnostic thinking and be highly vigilant for the possibility of secondary primary tumors in the trachea. They should comprehensively assess using various examination methods to improve the early diagnosis accuracy and avoid the misdiagnosis and missed diagnosis， thereby providing the best treatment opportunity for the patients.

Key words: Tracheal adenoid cystic carcinoma, Radiotherapy, Second primary malignant tumor, Case report