Primary tracheal tumors are very rare, with only about 1 patient per million diagnosed each year, but over 90% of tracheal tumors are malignant, and the incidence of tracheal tumors is much lower than that of pharyngeal and endobronchial tumors. What are the types of tracheal tumors? The two most common tissue types of primary malignant tracheal tumors are: squamous cell carcinoma and adenoid cystic carcinoma, followed commonly by carcinoid and mucinous epidermoid carcinoma. Approximately 10% of primary tracheal tumors are benign, with squamous cell papilloma being the most common, while other types include pleomorphic adenoma, granulosa cell tumor, and benign chondrosarcoma. The most common secondary tumors of the trachea are direct invasion of the trachea by peripheral tumors, such as papillary or follicular carcinoma of the thyroid, advanced lung cancer or esophageal cancer, and there are also reports of distant tumors metastasizing to the trachea. Multiple carcinomas of the trachea are more common and have been reported in the literature as high as 28%. What are the manifestations caused by tracheal tumors? The most common clinical signs and symptoms are hemoptysis, cough, shortness of breath after activity and wheezing or asthma. Dysphagia and hoarseness are less common, but the presence of these two symptoms often indicates a poor prognosis. Hemoptysis is the most common symptom of squamous carcinoma of trachea, so the diagnosis is usually timely based on the symptoms. Adenoid cystic carcinoma usually presents as wheezing or asthma, which often delays the diagnosis of tumor due to misdiagnosis as asthma. I suspect a tracheal tumor, how do I get tested? Tracheoscopy and imaging are the most commonly used tests to diagnose tracheal tumors. Adenoid cystic carcinoma often spreads under the tracheal mucosa, so it is recommended to biopsy the normal looking tracheal mucosa located farther away from the tumor during tracheoscopy. Chest plain film is difficult to diagnose tracheal tumors, while chest CT diagnoses or tracheal body image diagnoses 95% of tracheal tumors and can be used to identify mediastinal tumors. Current pulmonary function tests can differentiate tracheal tumors from asthma, and many patients misdiagnosed with asthma have pulmonary function tests that suggest tracheal tumors.