[Clinicopathological and genetic characteristics of bronchial sialadenoma papilliferum: report of four cases].

Objective

To investigate the clinicopathological, immunophenotypic, and molecular genetic features of bronchial sialadenoma papilliferum (BSP).

Methods

Four cases of BSP collected at the Shanghai Pulmonary Hospital from May 2018 to June 2021 were retrieved and analyzed. These cases were evaluated for their clinical, histological, immunohistochemical (IHC) and genomic features. The patients were followed up and relevant literature was reviewed.

Results

All four patients were male, aged from 55 to 75 years (mean 62 years), with tumor diameter of 6 to 21 mm (mean 13.5 mm), and lesions were located in the left lower lobe (n=2), right lower lobe (n=1), and trachea (n=1). They were characterized by a combination of surface exophytic endobronchial papillary proliferation and an endophytic two-cell layered ductal structure. IHC staining showed that CK7 and EMA were strongly positive in ductal epithelium; p63, p40, CK5/6 were positive in ductal and papillary basal cells; SOX10 was positive in ductal epithelium and basal cells; S-100 was positive in basal cells and ductal epithelium in two cases. Next generation sequencing showed that two cases harbored BRAF V600E mutation.

Conclusions

BSP is an extremely rare primary lung tumor arising from the salivary gland under bronchial mucosa. The primary treatment choice of this tumor is complete surgical resection. The diagnosis and differential diagnosis of this tumor depend on classic histomorphologic and IHC features, and BRAF V600E gene mutation can be detected.