Pulmonary papillary adenoma: comprehensive clinicopathologic analysis of 10 cases and molecular genetic analysis of 7 cases.

Pulmonary papillary adenoma (PPA) constitutes a relatively uncommon type of lung neoplasm, which gives rise to a diagnostic intricacy. Owing to the paucity, our understanding of this disease remains far from comprehensive, and a thorough molecular investigation around PPA has been conspicuously lacking. The current study amassed a group of 10 cases of PPA that had been precisely diagnosed. We collected their clinical particulars and utilized next-generation sequencing (NGS) technology to examine the genetic mutations in 7 of these cases. The study population comprised 3 female and 7 male patients, with a median age of 52.9 years. The tumor sizes ranged from 0.8 to 3.8 cm. Seven patients were asymptomatic, while three patients manifested respiratory symptoms. Through the application of NGS, a wide array of mutation patterns was identified in the 7 cases, implicating pathways such as Wnt, RTK/RAS, PI3K, and Cell Cycle/Checkpoint. More precisely, mutations in genes such as MAP2K1 (1/7), AKT1 (1/7), NF1 (1/7), APC (2/7), EGFR (1/7), NBN (1/7), and CTNNB1 (1/7) were detected. The pathways most commonly involved were the Wnt pathway (3/7, APC and CTNNB1) and the RTK/RAS pathway (3/7, MAP2K1, NF1, and EGFR). As of now, all patients are still alive, without any evidence of recurrence or metastasis. This study has significantly enlarged the PPA case database and has suggested that PPA is a tumor type possessing unique and relatively complex molecular characteristics.