Pulmonary pleomorphic adenoma (PA) is a rare salivary gland-type neoplasm, which predominantly occurs in the proximal airway. Rearrangement of the pleomorphic adenoma gene 1 (PLAG1) is the most frequent genetic event in PAs of salivary glands. However, whether pulmonary PA also harbors PLAG1 rearrangement has not been elucidated. Here, we present a case of pulmonary PA, located at the middle lobar bronchus, in a 54-year-old man. CTNNB1-PLAG1 gene fusion was identified by reverse transcription-polymerase chain reaction using formalin-fixed paraffin-embedded tissue (FFPE). Furthermore, immunohistochemical analysis revealed nuclear expression of PLAG1 in all tumor cells. To the best of our knowledge, this is the first reported case of pulmonary PA with CTNNB1-PLAG1 fusion and PLAG1 expression. Our case illustrates the possibility that pulmonary PA could be underpinned by recurrent PLAG1 translocations akin to salivary gland PA.

中文翻译：

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肺多形性腺瘤患者CTNNB1-PLAG1基因重排的鉴定。

肺多形性腺瘤（PA）是一种罕见的唾液腺型肿瘤，主要发生在近端气道中。多形性腺瘤基因1（PLAG1）的重排是唾液腺PAs中最常见的遗传事件。但是，尚不清楚肺PA是否也携带PLAG1重排。在这里，我们介绍了一例54岁男性位于肺中叶支气管的肺部PA。使用福尔马林固定石蜡包埋的组织（FFPE）通过逆转录-聚合酶链反应鉴定了CTNNB1-PLAG1基因融合体。此外，免疫组织化学分析揭示了PLAG1在所有肿瘤细胞中的核表达。据我们所知，这是首次报道的具有CTNNB1-PLAG1融合和PLAG1表达的肺部PA病例。