Multiplanar reconstruction MR image of primary adenoid cystic carcinoma of the central airway: (MPR of central airway adenoid cystic carcinoma)

Radiological and Clinical Features and Outcomes of Patients with Primary Pulmonary Salivary Gland-Type Tumors

Aim

To analyze the radiological, clinical, and prognostic features of primary pulmonary salivary gland-type tumors (SGTs) and improve their diagnosis.

Materials and Methods

We retrospectively collected clinical and pathological data for 32 SGT cases confirmed by pathology and analyzed their radiological features, clinical presentations, and treatment outcomes.

Results

Mucoepidermoid carcinoma (MEC) was more likely to occur in younger patients than was adenoid cystic carcinoma (ACC) (35 ± 15 years vs 48 ± 16 years, p=0.038). MEC was equally distributed between both sexes, whereas ACC was more frequent in females (66.7%). The main presenting symptom of SGT was cough (56.3%), followed by dyspnea (40.6%), associated with the tumor location. ACC more frequently involved the trachea or main bronchus (86.7% vs 25.0%, p=0.001) and more commonly presented as lobulated or circumferential thickening than MEC (93.3% vs 37.5%, p=0.002). MEC more frequently presented as obvious enhancement than ACC (68.8% vs 31.3%, p=0.001). CT findings suggestive of airway obstructive disease were more likely to be observed with MEC than ACC (73.3% vs 25.0%; p=0.021). The SUVmax in 8 of 10 patients with PET/CT data exceeded 2.2 but was less than 6.0. The overall survival (OS) at 3 and 5 years was 90.9% and 72.2% in all patients, respectively. Tumor-node-metastasis (TNM) stage, surgery, and patient age were associated with OS (p ≤ 0.001, p=0.001, and p=0.001, respectively).

Conclusion

SGTs commonly occur in patients at a young age and are associated with weak invasive features and a good prognosis. The predominant site and CT characteristics are significantly different between ACC and MEC.

Tracheobronchial gland tumors

BACKGROUND

Tracheal tumors are uncommon, making up only 0.2% of all respiratory malignancies in the United States. One consequence of this low incidence is that few centers accumulate meaningful experience. Another is the lack of awareness of effective therapy. Bronchial gland tumors demonstrate oncologic diversity and include benign, low-grade, and high-grade malignant tumors.

METHODS

We reviewed the present knowledge of bronchial gland tumors of the trachea, carina, and bronchi, including the epidemiology, presentation, evaluation, tumor types, and treatment options.

RESULTS

The malignant bronchial gland tumors, adenoid cystic carcinoma and mucoepidermoid carcinoma, are far more common than benign mucinous cystadenoma or pleomorphic adenoma. Complete resection of localized tumors has excellent long-term results in symptomatic benign tumors. The disease-free survival after resection of malignant tumors is limited by distant metastasis and regional disease, while local recurrence is uncommon. Postoperative mediastinal radiation is now accepted adjuvant therapy. Experience at our institute demonstrates a significant survival advantage for patients with complete resection compared to unresectable patients.

CONCLUSIONS

Expanding knowledge of diagnostic evaluation and surgical therapy can improve the long-term survival of patients with tracheobronchial gland tumors.

[Thoracic adenoid cystic carcinomas]

Adenoid cystic carcinomas in the trachea are rare, but represent around 40% of all tracheal tumours. Other intrathoracic localisations include the carena or proximal airways. Adenoid cystic carcinoma's growth rate is slow so that it is frequently diagnosed at an advanced stage. Pathological identification may be difficult. Treatment in limited tumours is based upon surgical resection often combined to radiotherapy because of close surgical margins. Radiotherapy dose may vary between 45 and 65 Gy according to margins status. Five-year survival rates of 65-80% have been reported after surgery or surgery and postoperative radiotherapy. Among inoperable patients treated with exclusive radiotherapy for tracheal tumours (including adenoid cystic but also squamous cell carcinomas of poorer prognosis), the recommended delivered dose should be over 60 Gy. Five-year survival rate in these very heterogeneous series may vary between 12 and 27%. Local or metastatic recurrences may occur very lately. They are considered chemo-resistant and targeted therapies may prove to be effective in the future.

Radiographic assessment of airway tumors

The initial imaging evaluation of a patient with a suspected tracheal abnormality is the chest radiograph, which is poor for detection of central airway lesions. Prior to the development of CT, planar tomography was performed to better evaluate the deep layers of the chest. Tomography is rarely performed today for chest imaging. There have been major advances in chest radiography techniques secondary to improvements in electronics and computer technology that might ultimately improve plain film assessment of the central airways.