Ricaurte Luisa María, Arrieta Oscar, Zatarain-Barrón Zyanya Lucia, Cardona Andrés F
Foundation for Clinical and Applied Cancer Research - FICMAC, Bogotá, Colombia,
Thoracic Oncology Unit, National Cancer Institute (INCan), México City, México.
Lung Cancer (Auckl). 2018 Aug 23;9:57-63. doi: 10.2147/LCTT.S137410. eCollection 2018.
Fetal adenocarcinoma of the lung (FLAC) is a rare tumor. It accounts for ~0.1%-0.5% of all pulmonary neoplasms. Due to its rarity, much of the world literature regarding FLAC comes from case reports and case series. FLAC is an adenocarcinoma resembling developing fetal lung in its pseudoglandular stage (8-16 weeks of gestation). It is distinguishable from pulmonary blastoma (PB) because it lacks the mesenchymal component which is a hallmark finding in PB. Due to differences in histopathology and clinical course, FLAC has been further categorized into low-grade (L-FLAC) and high-grade (H-FLAC) forms. L-FLAC displays low nuclear atypia and prominent morule formation and has a pure pattern. H-FLAC typically presents with at least 50% fetal morphology, and is often associated with other conventional types of lung adenocarcinoma. FLAC expresses neuroendocrine markers and thyroid transcription factor 1 in most cases. L-FLAC has an aberrant nuclear/cytoplasmic expression of β-catenin and presents mutations in this gene. H-FLAC overexpresses p53. These tumors have a very low frequency of mutations in and ; it is thought that they are different from a molecular point of view to conventional lung adenocarcinomas. Approximately 25%-40% of patients are asymptomatic at presentation; most of them are incidental findings on chest radiographs. H-FLAC is more common in elderly male patients, with a heavy smoking history. L-FLAC tends to occur in young females. Patients with L-FLAC are usually diagnosed with stage I-II disease, while patients with H-FLAC usually present with a more advanced-stage disease. Poor prognostic factors for FLAC are thoracic lymphadenopathy, metastases at diagnosis, and tumor recurrence; however, the 10-year survival for FLAC is estimated at 75%.
胎儿肺腺癌（FLAC）是一种罕见肿瘤。它占所有肺部肿瘤的约0.1%-0.5%。由于其罕见性，世界上关于FLAC的许多文献都来自病例报告和病例系列。FLAC是一种腺癌，在其假腺泡期（妊娠8-16周）类似于发育中的胎儿肺。它与肺母细胞瘤（PB）不同，因为它缺乏PB中作为标志性发现的间叶成分。由于组织病理学和临床过程的差异，FLAC已进一步分为低级别（L-FLAC）和高级别（H-FLAC）形式。L-FLAC显示低核异型性和显著的桑椹体形成，且具有纯模式。H-FLAC通常至少有50%的胎儿形态，并且常与其他传统类型的肺腺癌相关。大多数情况下，FLAC表达神经内分泌标志物和甲状腺转录因子1。L-FLAC具有β-连环蛋白的异常核/细胞质表达，并在该基因中出现突变。H-FLAC过度表达p53。这些肿瘤在 和 中的突变频率非常低；从分子角度来看，它们被认为与传统肺腺癌不同。大约25%-40%的患者在就诊时无症状；其中大多数是胸部X线片上的偶然发现。H-FLAC在老年男性患者中更常见，有大量吸烟史。L-FLAC倾向于发生在年轻女性中。L-FLAC患者通常被诊断为I-II期疾病，而H-FLAC患者通常表现为更晚期的疾病。FLAC的不良预后因素是胸段淋巴结肿大、诊断时转移和肿瘤复发；然而，FLAC的10年生存率估计为75%。
