Ha X M, Yao Y Z, Sun L H, Xin C Y, Xiong Y
Department of Pathology, Miyun District Hospital of Beijing, Beijing 101500, China.
Department of Thoracic Surgery, Miyun District Hospital of Beijing, Beijing 101500, China.
Beijing Da Xue Xue Bao Yi Xue Ban. 2023 Apr 18;55(2):357-361. doi: 10.19723/j.issn.1671-167X.2023.02.023.
Placental transmogrification of the lung (PTL) is a very rare benign lung lesion. There are only about 40 cases reported in the literature. The imaging and histological features of PTL cases in the publication are various, most of which are cystic and a few of which are solid. Being extremely rare, the solid PTL is unknown to major pathologists and surgeons. We reported a case of solid PTL in the anterior mediastinum. The patient was a 52-year-old male with no history of smoking and without symptoms. During physical examination, chest CT revealed a circular low-density lesion with a maximum diameter of 2.9 cm beside the spine in the posterior basal segment of the left lower lobe of the lung. The wedge resection was performed by video-assisted thoracoscopy. Grossly, a round nodule was located underneath the visceral pleura. It was about 3.0 cm×3.0 cm×1.6 cm and the cut surface was grey-red, soft and spongy. Microscopically, the nodule was constituted of papillare, which resembled placental villi at low magnification. The axis of papillae was edema, in which some mild round cells with clear cytoplasm and CD10 positive staining aggregated and transitioned to immature adipocytes and amorphous pink materials deposited with a few of inflammatory cells infiltration. The surface of papillae was covered with disconti-nuous alveolar epithelium. Combined with the typical morphology and immunohistochemical characteristics of CD10 positive, the diagnosis was PTL. The patient was followed up for 1 year without recurrence and discomfort. So far, the pathogenesis of PTL is unclear. The major hypotheses include hamartoma, variant of emphysema and clonal hyperplasia of stromal cells. Based on the study of our case and publication, we speculate that the hyperplasia of stromal cells located in the alveolar septa might be the first step to form the solid PTL. With the progression of the disease, a typical unilateral cystic nodule develops as a result of secondary cystic degeneration due to the occlusive valve effect. Surgery is the only option for diagnosis and treatment of PTL. The clinician should make an individualized operation plan according to the clinical manifestations, location and scope of the lesion, and preserve the surrounding normal lung tissue as much as possible while completely removing the lesion. There is a favorable prognosis.
肺胎盘样化生（PTL）是一种非常罕见的良性肺病变。文献中仅报道了约40例。已发表的PTL病例的影像学和组织学特征各不相同，其中大多数为囊性，少数为实性。由于极为罕见，实性PTL对于大多数病理学家和外科医生来说并不了解。我们报告了一例位于前纵隔的实性PTL病例。患者为一名52岁男性，无吸烟史且无症状。体格检查时，胸部CT显示左肺下叶后基底段脊柱旁有一个最大直径为2.9 cm的圆形低密度病变。通过电视辅助胸腔镜进行了楔形切除术。大体上，一个圆形结节位于脏层胸膜下方。它约为3.0 cm×3.0 cm×1.6 cm，切面呈灰红色，质地柔软且呈海绵状。显微镜下，结节由乳头构成，低倍镜下类似胎盘绒毛。乳头轴心为水肿，其中一些细胞质清晰的轻度圆形细胞聚集并转变为未成熟脂肪细胞，同时有一些无定形粉红色物质沉积，并伴有少量炎症细胞浸润。乳头表面覆盖有不连续的肺泡上皮。结合典型形态及CD10阳性的免疫组化特征，诊断为PTL。患者随访1年无复发及不适。迄今为止，PTL的发病机制尚不清楚。主要假说是错构瘤、肺气肿变体和基质细胞的克隆性增生。基于我们的病例及已发表文献的研究，我们推测位于肺泡间隔的基质细胞增生可能是形成实性PTL的第一步。随着疾病进展，由于闭塞瓣膜效应导致继发性囊性变，会形成典型的单侧囊性结节。手术是PTL诊断和治疗的唯一选择。临床医生应根据临床表现、病变位置和范围制定个体化手术方案，并在完全切除病变的同时尽可能保留周围正常肺组织。预后良好。
