Most commonly described as sporadic, pulmonary adenocarcinoma with enteric differentiation (PAED) is a rare variant of invasive lung cancer recently established and recognised by the World Health Organization. This tumour is highly heterogeneous and shares several morphological features with pulmonary and colorectal adenocarcinomas. Our objective is to summarise current research on PAED, focusing on its immunohistochemical and molecular features as potential tools for differential diagnosis from colorectal cancer, as well as prognosis definition and therapeutic choice. PAED exhibits an ‘entero-like’ pathological morphology in more than half cases, expressing at least one of the typical immunohistochemical markers of enteric differentiation, namely CDX2, CK20 or MUC2. For this reason, this malignancy appears often indistinguishable from a colorectal cancer metastasis, making the differential diagnosis laborious. Although standard diagnostic criteria have not been established yet, in the past few years, a number of approaches have been addressed, aimed at defining specific immunohistochemical and molecular signatures. Based on previously published literature, we have collected and analysed molecular and immunohistochemical data on this rare neoplasm, and have described the state of the art on diagnostic criteria as well as major clinical and therapeutic implications.The analysis of data from 295 patients from 58 published articles allowed us to identify the most represented immunohistochemical and molecular markers, as well as major differences between Asian PAEDs and those diagnosed in European/North American countries. The innovative molecular approaches, exploring driver mutations or new gene alterations, could help to identify rare prognostic factors and guide future tailored therapeutic approaches to this rare neoplasm.

中文翻译：

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肺肠腺癌：概述

最常被描述为具有肠分化的散发性肺腺癌 (PAED) 是一种罕见的侵袭性肺癌变体，最近得到世界卫生组织的认可和认可。这种肿瘤具有高度异质性，并与肺腺癌和结直肠腺癌具有多种形态学特征。我们的目标是总结目前对 PAED 的研究，重点关注其免疫组织化学和分子特征，作为结直肠癌鉴别诊断的潜在工具，以及预后定义和治疗选择。PAED 在超过一半的病例中表现出“肠样”病理形态，表达至少一种典型的肠分化免疫组化标志物，即 CDX2、CK20 或 MUC2。为此原因，这种恶性肿瘤通常与结直肠癌转移无法区分，因此鉴别诊断很费力。尽管尚未建立标准诊断标准，但在过去几年中，已经解决了许多方法，旨在定义特定的免疫组织化学和分子特征。根据之前发表的文献，我们收集和分析了这种罕见肿瘤的分子和免疫组织化学数据，并描述了诊断标准的最新技术以及主要的临床和治疗意义。对来自 58 名已发表的 295 名患者的数据进行分析文章使我们能够确定最具代表性的免疫组织化学和分子标志物，以及亚洲 PAED 与欧洲/北美国家诊断出的 PAED 之间的主要差异。