支气管腺瘤（BA）是一种罕见的支气管肿瘤，具有双层结构，包括基底细胞层和表浅细胞层，预后良好。然而，近期的文献提出了一种可能的BA变异概念。我们从中心采集了17例BA的临床数据、形态学、免疫表型和分子变化，并进行了回顾性分析。我们还收集了先前文献中BA的分子变化，并总结了BA的假定驱动突变。在17例BA中，有13例经典病例呈双层结构，包括9例近端型和4例远端型BA。值得注意的是，我们还鉴定出3例缺乏连续基底细胞层的病例，包括2例混合型BA的单层病变（在某些区域未检测到基底细胞）和1例单层BA样病变（完全未检测到基底细胞）。单层细胞病变的免疫组化发现更接近于最小侵袭性腺癌。我们还发现一例BA转化为侵袭性腺癌，并伴随着TP53、JAK2、NF1和RB1基因的突变。结合先前的文献，62个BA病变中最常见的假定驱动基因突变是EGFR（25/62；41%）和BRAF（21/62；34.4%）。典型的BA具有双层细胞结构；然而，还有一种假定的BA变异，具有单层细胞结构并缺乏基底细胞层。BA转化为侵袭性腺癌是不寻常的，但是可能会发生。 ©作者（2023年）。开放获取。本文受创意共同体国际许可协议的许可。

Bronchiolar adenoma (BA) is a rare tumor of the bronchioles with a double-layer structure, including the basal cell layer and the superficial cell layer, and it has a good prognosis. However, the concept of a putative variant of BA has been proposed in the recent literature.Data on 17 cases of BA were collected from our center. The clinical data, morphology, immunophenotype, and molecular changes were retrospectively analyzed. We also collected the molecular changes in BA reported in the previous literature and summarized the putative driver mutations of BA.Out of 17 BAs, 13 were classic cases with a double-layer structure, including 9 proximal-type and 4 distal-type BAs. Of note, we also identified 3 cases that lacked a continuous basal cell layer, including 2 cases of mixed-type BA with monolayered lesions (basal cells were undetected in some areas) and 1 case of a monolayered BA-like lesion (basal cells were completely undetected). The immunohistochemical findings of monolayer cell lesions were closer to those of minimally invasive adenocarcinoma. We also found one case in which BA transformed into invasive adenocarcinoma accompanied by mutations in the TP53, JAK2, NF1 and RB1 genes. Combined with the previous literature, the most common putative driver gene mutations in 62 BA lesions were EGFR (25/62; 41%) and BRAF (21/62; 34.4%).Typical BA has a double-layer cell structure; however, there is also a putative variant of BA, which has a monolayer cell structure and lacks the basal cell layer. Transformation from BA into invasive adenocarcinoma is unusual but can occur.©The Author(s) 2023. Open Access. This article is licensed under a Creative Commons CC-BY International License.