Clinicopathological and Prognostic Comparison of Primary Pulmonary Adenoid Cystic Carcinoma and Mucoepidermoid Carcinoma: A Single-Center Study

Objectives: Primary pulmonary salivary gland-type tumors are rare neoplasms, with adenoid cystic carcinoma (ACC) and mucoepidermoid carcinoma (MEC) being the most common histological subtypes. This study aimed to compare the clinicopathological characteristics, treatment outcomes, and survival of patients with ACC and MEC. Methods: We retrospectively analyzed 59 patients diagnosed with primary pulmonary salivary gland-type tumors between 2016 and 2025. The cohort included 37 patients with ACC and 22 with MEC. Demographic, clinicopathological, treatment-related, and survival data were compared between the two groups. Results: ACC was significantly associated with tracheal localization (62.2% vs. 13.6%, p < 0.001), positive surgical margins (35.1% vs. 9.1%, p = 0.019), and a higher recurrence/metastasis rate (32.4% vs. 4.5%, p = 0.020). Overall survival did not differ significantly between ACC and MEC (p = 0.530), whereas disease-free survival was significantly lower in the ACC group (p = 0.009). Positive surgical margins were associated with inferior disease-free survival (p = 0.036). Among ACC patients, a predominantly solid histopathological pattern was significantly associated with worse overall survival (p = 0.034). Conclusions: Although ACC and MEC are traditionally grouped as pulmonary salivary gland-type tumors, they demonstrate distinct clinicopathological and prognostic characteristics. ACC is associated with greater surgical complexity, higher recurrence risk, and poorer disease-free survival, emphasizing the importance of achieving negative surgical margins and maintaining long-term follow-up.