Primary pulmonary salivary gland-type tumors in cytopathology practice: A systematic review and meta-analysis

Abstract

Background: Primary pulmonary salivary gland-type tumors (PSGTs) are rare but clinically significant tumors that originate from the submucosal glands of the tracheobronchial tree. Cytologic samples taken during bronchoscopy are a key component of preoperative evaluation. However, cytologic diagnosis remains challenging because of the submucosal growth and morphologic overlap of PSGTs. In addition, current knowledge of the cytohistologic correlation of PSGTs is fragmented. The objective of this study was to assess the effectiveness of cytologic diagnoses of PSGTs. Methods: A comprehensive, systematic literature search of the PubMed database was conducted to identify studies with cytologic and histologic diagnoses of PSGTs. Comprehensive data on diagnostic and clinical factors, when available, were collected for all individual patients. The data were tabulated in Microsoft Excel and analyzed using OpenMeta (Analyst) software. Results: In total, 49 studies comprising 106 patients were identified. Final cytohistologic concordance was demonstrated in 48.1% of cases. Fine-needle aspiration showed the highest sensitivity (75.0%), followed by bronchial/tracheal washing (38.1%), and bronchial brushing (34.2%). Adenoid cystic carcinoma was the most common histologic subtype, accounting for 67 cases, followed by mucoepidermoid carcinoma, which accounted for 27 cases. Conclusions: The cytologic diagnosis of rare PSGTs remains challenging. Overall, cytohistologic concordance was 48.1%. However, fine-needle aspiration demonstrated greater diagnostic accuracy than exfoliative cytology and may facilitate a more accurate preoperative assessment.