Department of Obstetrics/Gynecology (J.D.) Department of Obstetrics/Gynecology, Division of Gynecologic Oncology (D.M.O.), The Ohio State University College of Medicine Department of Pathology, The Ohio State University (W.C.), Columbus, Ohio Department of Pathology, Johns Hopkins Medical Institutions, Baltimore, Maryland (B.M.R.).
Int J Gynecol Pathol. 2020 May;39(3):238-246. doi: 10.1097/PGP.0000000000000598.
Placental site nodule (PSN) is a benign lesion composed of chorionic-type intermediate trophoblastic cells and is typically an incidental finding in uterine or endocervical curettage specimens. Epithelioid trophoblastic tumor (ETT) and placental site trophoblastic tumor (PSTT) are intermediate trophoblastic neoplasms of chorionic and implantation site types, respectively. ETT is speculated to be the neoplastic counterpart of PSN. The term atypical placental site nodule (APSN) has been proposed for PSN-type lesions displaying one or more concerning features, including larger size/more abundant lesional tissue, more extensive plaque-like growth, increased cellularity with more cohesive nests and cords of cells, a greater extent/distribution of necrosis, increased atypia, mitotic activity, and/or a Ki-67 proliferation index greater than usually encountered in the typical PSN. It has been proposed that APSN is an intermediary lesion between PSN and intermediate trophoblastic tumors, more commonly ETT but also PSTT. We report a case of a 39-yr-old woman who developed abnormal uterine bleeding 44 mo after her last recognized pregnancy. An endometrial curettage specimen demonstrated an APSN with some features concerning for an intermediate trophoblastic tumor. A hysterectomy specimen demonstrated residual APSN with foci consistent with emerging PSTT and ETT. This case illustrates the earliest form of PSTT and ETT arising in association with an APSN and supports interpretation of APSN as an intermediary lesion between typical PSN and intermediate trophoblastic tumors.
胎盘部位结节（PSN）是一种良性病变，由绒毛型中间滋养细胞组成，通常是在子宫或宫颈刮宫标本中偶然发现的。上皮样滋养细胞肿瘤（ETT）和胎盘部位滋养细胞肿瘤（PSTT）分别是绒毛型和植入部位型的中间滋养细胞肿瘤。ETT 被推测为 PSN 的肿瘤对应物。对于表现出一个或多个令人担忧特征的 PSN 样病变，提出了“非典型胎盘部位结节（APSN）”一词，这些特征包括更大的大小/更丰富的病变组织、更广泛的斑块状生长、细胞增多、更具黏附性的巢状和索状细胞、更大程度/分布的坏死、更高的异型性、有丝分裂活性和/或 Ki-67 增殖指数高于典型 PSN 中通常遇到的水平。有人提出，APSN 是 PSN 和中间滋养细胞肿瘤之间的中间病变，更常见的是 ETT，但也有 PSTT。我们报告了一例 39 岁女性，她在最后一次被确认怀孕后 44 个月出现异常子宫出血。子宫内膜刮宫标本显示 APSN 具有一些中间滋养细胞肿瘤的特征。子宫切除标本显示残留的 APSN 有符合新兴 PSTT 和 ETT 的病灶。该病例说明了与 APSN 相关的 PSTT 和 ETT 的最早形式，并支持将 APSN 解释为典型 PSN 和中间滋养细胞肿瘤之间的中间病变。
