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.