Tracheal tumors are categorized into benign and malignant types. Malignant tracheal tumors are further classified as primary or secondary. In children, benign tracheal tumors are more common, whereas malignant ones are more prevalent in adults. The incidence is comparable between men and women and is most frequently observed in individuals aged 30–50 years.
Pathology
Benign Tracheal Tumors
Histologically, these include papillomas, chondromas, and fibromas.
Malignant Tracheal Tumor
These can be divided into the following three categories:
- Epithelial Tumors: These include squamous cell carcinoma, adenoid cystic carcinoma, carcinoid tumors, adenocarcinoma, and mucoepidermoid carcinoma.
- Mesenchymal Tumors: These include chondrosarcoma, fibrosarcoma, and leiomyosarcoma.
- Lymphomas: These include non-Hodgkin’s lymphoma and Hodgkin’s lymphoma.
Among malignant tracheal tumors, squamous cell carcinoma is the most common type, accounting for approximately 50% of cases. It is more frequently seen in smokers and can occur in any part of the trachea, particularly in the membranous portion. These tumors typically grow in a cauliflower-like pattern, often ulcerate, and obstruct the lumen. The disease tends to progress rapidly and may invade adjacent tissues. Adenoid cystic carcinoma is the second most common malignancy, accounting for about 30% of cases. It is often located in the upper third of the trachea, is considered low-grade malignancy, grows slowly, and has a relatively favorable prognosis.
Lymphatic metastasis is the primary route of spread for malignant tracheal tumors, while hematogenous metastasis is relatively uncommon.
Clinical Manifestations
The symptoms of tracheal tumors largely depend on the size, growth rate, mobility of the tumor, potential ulceration, and the degree of tracheal narrowing. The clinical features primarily include:
- Cough and hemoptysis.
- Dyspnea, wheezing, and stridor.
- Recurrent pneumonia.
- Hoarseness and dysphagia in advanced stages.
- Symptoms caused by distant tumor metastases.
Diagnosis
The early-stage clinical symptoms and signs of tracheal tumors are often nonspecific. Persistent chronic irritative dry cough, progressive dyspnea, or recurrent episodes of pneumonia or asthma that are unresponsive to medical therapy should raise suspicion for tracheal tumors.
Chest CT is considered the best imaging method for diagnosing tracheal tumors. The findings often include an intraluminal soft tissue mass, typically eccentric in nature, with thickened tracheal walls and irregular luminal narrowing. Enlarged lymph nodes near the trachea may also be observed, suggesting possible metastasis. CT three-dimensional reconstruction can provide a clearer depiction of the tumor's morphology.
Bronchoscopy is another critical diagnostic tool for tracheal tumors. It helps determine the location, size, morphology of the tumor, and the degree of luminal obstruction. It also provides an initial assessment of tumor malignancy and allows for biopsy to confirm pathological diagnosis. For larger tumors, preoperative esophagography or esophagoscopy may be necessary to evaluate possible esophageal involvement, assess surgical feasibility, and distinguish between tracheal tumors and tumors originating from the esophagus.
Treatment
The preferred treatment for tracheal tumors is surgical resection and reconstruction. Other therapeutic approaches include bronchoscopic tumor resection, intraluminal stent placement, and radiotherapy.
Surgical Treatment
For malignant tracheal tumors or benign tumors that cannot be completely excised through endoscopic methods, tracheal resection and reconstruction should be considered. The most common surgical approach is sleeve resection with end-to-end anastomosis, which, when performed early, produces favorable outcomes. Tumors located at the tracheal carina or those involving the carina and bronchus may require carinal resection and reconstruction.
Accurate preoperative assessment of the extent of the lesion and the length of the trachea that can be resected is critical. For resections within 5 cm, primary anastomosis and reconstruction are typically feasible. If the lesion is extensively invasive, resulting in excessive tension at the anastomotic site that could compromise healing, artificial tracheal replacement, tumor excision with tracheostomy, or tracheal wall resection and reconstruction may be considered, often supplemented by radiotherapy. Paralysis of the recurrent laryngeal nerve, superior vena cava obstruction syndrome, or distant metastases represent relative contraindications to surgery.
Endoscopic Treatment
For smaller benign tracheal tumors with a narrow base, endoscopic resection may achieve therapeutic goals. For larger malignant tracheal tumors that cannot be radically resected, techniques such as laser ablation, cryotherapy, argon-helium knives, placement of radioactive particles, or intraluminal stents through rigid bronchoscopy or fiberoptic bronchoscopy can alleviate airway obstruction and control bleeding, thereby relieving symptoms.
Radiotherapy
This is applicable for inoperable malignant tracheal tumors and as adjuvant therapy postoperatively. For tumors that are too large or involve significant external invasion, reducing them through radiotherapy may improve surgical feasibility.