Department of Respiratory and Critical Care Medicine, People's Hospital of Honghuagang District.
Department of Oncology, Second Affiliated Hospital of Medical University, Zunyi, China.
Medicine (Baltimore). 2021 Feb 19;100(7):e24634. doi: 10.1097/MD.0000000000024634.
Fetal adenocarcinoma of the lung (FLAC) is an extremely rare tumor. Due to its rarity, most of the knowledge about FLAC comes from case reports. FLAC is an invasive adenocarcinoma that is similar to the fetal lung in the pseudo-glandular stage (8-16 weeks of gestation). Owing to the differences in histopathology and clinical process, FLAC has been further divided into low-level (L-FLAC) and high-level (H-FLAC). H-FLAC is usually associated with other conventional types of lung adenocarcinoma. Lung adenocarcinoma that produces alpha-fetoprotein (AFP) is a rare type of lung cancer. Its characteristics have not been fully elucidated.
We recently encountered this type of FLAC in a 51-year-old female patient. A computed tomography (CT) scan of the chest revealed a 74 × 51-mm sized tumor in the lingual segment of the superior lobe of the left lung. Among the tumor markers, serum AFP was elevated (816.2 ng/mL).
PRIMARY DIAGNOSIS, INTERVENTIONS, AND OUTCOMES: The diagnosis of FLAC in this patient was confirmed by bronchoscopy with lung biopsy. Through a thoracoscope, left lung pneumonectomy, and mediastinal lymph node dissection were performed. The postoperative pathological results were consistent with the preoperative diagnosis of H-FLAC. Western blotting showed the difference in the AFP expression between the normal lung tissue and the cancerous lung tissue. Eventually, the diagnosis was AFP-producing H-FLAC. Using an immunohistochemical marker for AFP, cancer cells were shown to express AFP, specifically in their nuclei. After the operation, the patient underwent conventional chemotherapy. Her serum AFP gradually decreased over the course of 2 weeks.
Presently, specific tumor markers for the diagnosis of lung cancer have not been established. To the best of our knowledge, this is the first case of abnormal AFP expression in a patient with H-FLAC. It may provide a basis for the clinical diagnosis of H-FLAC, a rare tumor, and AFP may be considered as a specific tumor marker.
肺胎儿腺癌（FLAC）是一种极其罕见的肿瘤。由于其罕见性，大多数关于 FLAC 的知识来自病例报告。FLAC 是一种侵袭性腺癌，类似于假腺期（妊娠 8-16 周）的胎儿肺。由于组织病理学和临床过程的差异，FLAC 进一步分为低级别（L-FLAC）和高级别（H-FLAC）。H-FLAC 通常与其他常规类型的肺腺癌相关。产生甲胎蛋白（AFP）的肺腺癌是一种罕见的肺癌类型。其特征尚未完全阐明。
我们最近在一名 51 岁女性患者中遇到了这种类型的 FLAC。胸部计算机断层扫描（CT）显示左肺上叶舌段有一个 74×51mm 大小的肿瘤。在肿瘤标志物中，血清 AFP 升高（816.2ng/mL）。
主要诊断、干预和结果：通过支气管镜肺活检确诊该患者为 FLAC。通过胸腔镜进行左肺全肺切除术和纵隔淋巴结清扫术。术后病理结果与术前诊断 H-FLAC 一致。Western blot 显示正常肺组织和癌组织中 AFP 表达的差异。最终诊断为 AFP 产生的 H-FLAC。使用 AFP 的免疫组织化学标志物，癌细胞表达 AFP，特别是在细胞核中。手术后，患者接受了常规化疗。她的血清 AFP 在 2 周内逐渐下降。
目前，尚未建立用于诊断肺癌的特定肿瘤标志物。据我们所知，这是首例 H-FLAC 患者 AFP 异常表达的病例。它可能为罕见肿瘤 H-FLAC 的临床诊断提供依据，并且 AFP 可被视为一种特定的肿瘤标志物。
