Expression of vasodilator-stimulated phosphoprotein in human placenta: possible implications in trophoblast invasion.

The vasodilator-stimulated phosphoprotein (VASP) is a 46 kDa protein present at the leading edge of migrating cells. Because trophoblastic cell migration and invasion are critical stages for the achievement of successful implantation and development of the placenta, we investigated VASP expression in different cell types of the human placenta throughout pregnancy by immunohistochemistry and Western blot analysis. We also studied the effect of leukaemia inhibitory factor (LIF) and transforming growth factor-beta1 (TGF-beta1) on the regulation of VASP expression in first trimester placental tissue explants. We found that VASP is expressed throughout pregnancy by a variety of cells in the human placenta. The strongest VASP immunoreactivity was observed in the first trimester. In these samples, the most intense immunoreactivity was in invasive trophoblasts, namely, extravillous cells of the anchoring villi, distal extravillous trophoblasts of cell columns, and also in cells of placental fibrinoids. We also found that LIF (but not TGF-beta1) has a stimulatory effect on VASP expression in placental explants. The strong VASP immunoreactivity in invasive trophoblasts suggests that this protein may be associated with trophoblastic cell motility and may have a role in implantation and trophoblastic cell invasion. We speculate that one of the effects of LIF in successful pregnancy may be its induction of VASP expression.     

A case of a placental site trophoblastic tumor

A rare placental site trophoblastic tumor (PSTT) in a 39-year-old female was studied. This tumor, protruding into the uterine cavity, was histologically similar to tumors in previously reported cases of PSTT. Ultrastructurally, the characteristic finding was the presence of perinuclear filaments. Also, the tumor cells were strongly positive for hPL by immunohistochemical method. These findings suggest that this was a tumor caused by neoplastic proliferation of the extravillous intermediate trophoblast.     

Osteopontin facilitates invasion in human trophoblastic cells via promoting matrix metalloproteinase-9 in vitro

Successful implantation of embryo and placentation depend on proper trophoblast proliferation and differentiated into specialized invasive trophoblast. However, little is known about the regulatory factors and mechanisms in trophoblast proliferation and differentiation. Osteopontin (OPN) is a member of the small integrin-binding ligand N-linked glycoprotein family and participates in cell adhesion and invasion. It has been identified that OPN is highly expressed in invasive trophoblasts in human placenta. In this study, we demonstrated that OPN is constitutively expressed in highly invasive phenotype of human choriocarcinoma cell lines of JAR and JEG-3 cells, and OPN could promote trophoblast proliferation and invasion, partly through promoting MMP-9 secretion. Inhibition of OPN will compromise the abilities of proliferation and invasion in JAR and JEG-3 cell lines. Our data showed that the expression of OPN in trophoblast may participate in placentation, OPN expression defects may be involved in gestational trophoblastic diseases.     

Expression of placental leucine aminopeptidase and adipocyte-derived leucine aminopeptidase in human normal and malignant invasive trophoblastic cells

We recently identified two novel aminopeptidases, placental leucine aminopeptidase (P-LAP) and adipocyte-derived leucine aminopeptidase (A-LAP). Enzymatically, P-LAP degrades oxytocin, vasopressin, and angiotensin III, while A-LAP degrades angiotensin II and kallidin. In this study we investigated the expression and localization of P-LAP and A-LAP in human trophoblastic cells in the normal placenta (n = 26), gestational choriocarcinoma (n = 8), and placental site trophoblastic tumor (n = 3). On immunoblot analysis both P-LAP and A-LAP proteins were detected in normal placenta and five choriocarcinoma tissues, as well as in two choriocarcinoma cell lines. Immunohistochemical staining of normal placental tissues demonstrated that P-LAP was not only localized in villous syncytiotrophoblasts but also highly expressed in extravillous trophoblasts (EVTs) invading the decidua or maternal spiral arteries. The expression level of P-LAP on these invasive EVTs reached a maximum during the late first to second trimesters of pregnancy, and it decreased in the third trimester. Similarly, A-LAP was strongly expressed in EVTs invading the decidua or spiral arteries in the second trimester of pregnancy, while it was weakly or moderately expressed in villous cytotrophoblasts or EVTs located in the cell columns. These two aminopeptidases were more strongly expressed in all eight choriocarcinomas and three placental site trophoblastic tumors and mainly localized to the intermediate-type trophoblastic tumor cells invading the uterine myometrium or stromal vessels. In summary P-LAP and A-LAP were predominantly expressed in the invasive phenotype of EVTs during placentation, as well as in the invasive tumor cells of trophoblastic neoplasms. These results suggest the involvement of these aminopeptidases in invasiveness of both normal and malignant intermediate-type trophoblasts possibly through degradation of specific peptide substrates.     

胎盘部位滋养细胞肿瘤的临床病理特点及鉴别诊断

目的了解胎盘部位滋养细胞肿瘤（ＰＳＴＴ）的临床病理特点及其鉴别诊断要点。方法对５例ＰＳＴＴ进行临床,光镜,电镜及免疫组化研究,并同时对比观察１０例绒癌及２例过度的胎盘部位反应（ＥＰＳ）。结果ＰＳＴＴ见于育龄妇女,前次妊娠多为足月产,常见症状为闭经及／或阴道出血。血清绒毛膜促性腺激素（ｈＣＧ）可有轻～中度升高。光镜下瘤细胞组成单一,仅见中间型滋养细胞,成片状,条索状穿插浸润于子宫平滑肌束间。血管浸润明显,却少有出血或坏死。分裂相少见。电镜下瘤细胞核周有丰富的中间丝。免疫组化表现为胎盘催乳素（ｈＰＬ）阳性而ｈＣＧ多为阴性。结论ＰＳＴＴ为一少见的滋养细胞肿瘤,具有独特的光镜,电镜及免疫组化特点,这些特点可与其它滋养细胞疾病鉴别     

The adhesion molecule CEACAM1 (CD66a, C-CAM, BGP) is specifically expressed by the extravillous intermediate trophoblast

CEACAM1 (CD66a, C-CAM, BGP) is an adhesion molecule of the carcinoembryonic antigen family which has been shown to be normally expressed at the apical pole of epithelial cells, including the apical pole of endometrial surface and glandular epithelia. The purpose of the present study was to investigate its expression pattern at the maternal-fetal interface, and thus to determine whether CEACAM1 could be implicated in the human implantation process. For this purpose, we performed immunohistochemistry using the 4D1/C2 monoclonal antibody (mAb) as well as flow cytometry and Western blot on isolated trophoblast populations. On the maternal side of the maternal-fetal interface, CEACAM1 was present in epithelial cells of pregnancy endometrium as well as in small endometrial vessels, whereas it was absent from decidual cells. On the fetal side, CEACAM1 was strongly expressed by the extravillous (intermediate) trophoblast at the implantation site, as well as by extravillous trophoblast cells with invasive phenotype in primary culture, as shown by flow cytometry and Western blot. Expression was also observed in placental villous core vessels but was absent from both villous cyto- and syncytiotrophoblasts throughout the pregnancy. We conclude that, given its specific expression pattern, CEACAM1 can be a useful marker for extravillous intermediate trophoblast and might be functionally implicated in mediating trophoblast/endometrial and/or trophoblast/endothelial interactions during the trophoblastic invasion of the endometrium.     

Neoplastic and non-neoplasti mediate trophoblasts: An immunohistochemical an structural study

Five cases of non-molar trophoblastic disease including one placental site trophoblastic tumor (PSTT), two exaggerated placental sites and two choriocarcinomas were compared with each other and with normal chorionic villi and placental site. This involved light microscopic, immunohistochemical and ultrastructural studies. Comparison of PSTT with choriocarcinoma suggested that the former represented a neoplastic transformation of placental site intermediate trophoblast. The PSTT showed a characteristic immunohistochemical distribution of human placental lactogen and human chorionic gonadotropin, resembling that of the placental site intermediate trophoblast. Placental site trophoblastic tumor cells were also characterized ultrastructurally by prominent perinuclear filaments, abundant rough endoplasmic reticulum, or both. Infiltrating intermediate trophoblasts in exaggerated placental sites were similar to PSTT cells rather than normal placental site intermediate trophoblasts. However cells with vacuolated cytoplasm or spindle-shaped intermediate trophoblastic ceils were observed more frequently in the PSTT than the exaggerated placental sites. The intermediate trophoblastic cells in the choriocarcinomas showed a morphologically transitional form from cytotrophoblastic cell to syncytiotrophoblastic cell, but did not share unique ultra-structural similarities with placental site intermediate trophoblasts.     

Gestationsbedingte Trophoblasterkrankungen

The non-villous forms of gestational trophoblastic disease (GTD) include a wide range of morphologic different lesions and cover a wide range of differential diagnosis. Choriocarcinomas (CCA) represent the most malignant form displaying a dimorphic pattern with proliferation of syncytio- and zytotrophoblast. An early start of chemotherapy is of great prognostic impact. Placental site nodule (PSN) and exaggerated placental site (EPS) are non-neoplastic lesions of the intermediate trophoblast without tumorous appearance, whereas placental site trophoblastic tumor (PSTT) and epitheloid trophoblastic tumor (ETT) represent tumorous neoplasms with a potential for local invasion and metastases. PSNs are incidental findings of highly polymorphic cells. In EPS chorionic villi are almost present, endometrial glands and spiral arteries are completely engulfed by intermediate trophoblastic cells without necroses. In PSTT the monomorphic, occasional multinucleated giant cells separating individual muscle fibers and charactersitically blood vessel walls are extensively replaced by trophoblastic cells and fibrinoid material. The ETT consists large necrotic areas with hyalinisation. Typically small blood vessels with preserved walls are located within the center of glycogen-rich monomorphous proliferation of trophoblastic cells.     

Extracellular pH modulates the secretion of fibronectin isoforms by human trophoblast

Differentiation of human trophoblast from the proliferative to the invasive phenotype takes place in a hypoxic and thus likely an acidic microenvironment. During differentiation, the secretion pattern of fibronectin isoforms changes. Therefore, we analysed the relation between extracellular pH, secretion of fibronectin splice variants and invasiveness. By means of immunohistochemistry and biochemistry, cellular non-oncofetal fibronectins were found in placental stroma and around extravillous trophoblast, whereas oncofetal isoforms only marked the extracellular matrix of extravillous trophoblast. In vitro, mesenchymal cells produced non-oncofetal fibronectins only, whereas choriocarcinoma cell lines, extravillous trophoblast and choriocarcinoma/trophoblast hybrid cells secreted both non-oncofetal and oncofetal isoforms. When the pH of the culture medium was either lowered or increased (between 6.0 and 8.0), the trophoblast hybrids, but not choriocarcinoma and mesenchymal cells, responded with increased secretion of fibronectins and a shift towards oncofetal isoforms. These changes were preserved after pH normalisation. Histochemical determination of local tissue acidity revealed that the site of the lowest detectable tissue pK coincided with the starting point of invasion, the proximal part of trophoblastic cell columns. Therefore, it is concluded that the local pH plays an important role as regulator of differentiation of human trophoblast as reflected by the synthesis of oncofetal fibronectins by the invasive phenotype of extravillous trophoblast.     

Human migrating extravillous trophoblasts express a cell surface peptidase, carboxypeptidase-M

We previously reported that a cell-surface aminopeptidase, dipeptidyl peptidase IV, is expressed on extravillous trophoblasts (EVT) and suggested the involvement of its enzyme activity in EVT migration. In this study, we examined the expression of another cell-surface peptidase, carboxypeptidase-M (CP-M), at human embryo implantation sites, which catalyses biologically active peptides at extracellular sites. CP-M was immunohistochemically detected on syncytiotrophoblast, but not on cytotrophoblasts in floating chorionic villi (9-12 weeks of gestation). At villus-anchoring sites, CP-M was weakly detected on some EVT in the distal part of the cell column. CP-M was clearly expressed on EVT in the trophoblastic shells and in the maternal vessels. In the decidua, almost all interstitial trophoblasts expressed CP-M. Flow cytometry and RT-PCR showed that CP-M expression was induced on the outgrown EVT in primary villous explant culture. The CP-M induction on cultured EVT under 20% O(2) concentration was significantly higher than that under 1% O(2) concentration. In invasion assays, migration of JEG-3 cells, a CP-M-bearing human choriocarcinoma cell line, was significantly enhanced by an inhibitor of CP-M, DL-mercaptomethyl-3-guanidino-ethyltiopropanoic acid (MGTA). These findings indicate that CP-M is a differentiation-related molecule for human EVT and suggest that CP-M expression on EVT is partially regulated by tissue oxygen concentration.     

Trophoblastic tumors: ultrastructural comparison of choriocarcinoma and placental-site trophoblastic tumor

Ten trophoblastic tumors, including seven classical choriocarcinomas, two choriocarcinomas with atypical histology, and one placental-site trophoblastic tumor (PSTT), were studied to compare their fine structural features. Ultrastructurally, the classical choriocarcinomas showed well-defined cytotrophoblasts and syncytiotrophoblasts. The cytotrophoblasts were primitive epithelial cells, while the syncytiotrophoblasts were complex cells with multiple nuclei and dense cytoplasm containing dilated endoplasmic reticulum, lysosomes, vesicles, and tonofilaments. The syncytiotrophoblast cell membranes often contained numerous microvilli. In the choriocarcinomas, scattered intermediate trophoblasts showed features transitional between the cytotrophoblasts and the syncytiotrophoblasts, with moderately complex cytoplasm containing some of the organelles found in the syncytiotrophoblasts. Histologically, the atypical choriocarcinomas showed a predominance of mononucleate and binucleate cells and indistinct syncytiotrophoblasts. Ultrastructurally, these atypical tumors were composed largely of intermediate trophoblasts, yet contained scattered syncytiotrophoblasts with microvilli in compressed aggregates. The PSTT was composed primarily of intermediate trophoblasts that contained prominent paranuclear filaments not seen in the intermediate trophoblasts of the choriocarcinomas. Rare cells resembling syncytiotrophoblasts were found in the PSTT, but no cytotrophoblasts were observed. Immunoreactivity for human chorionic gonadotropin and human placental lactogen was found in the intermediate trophoblasts and syncytiotrophoblasts of both the choriocarcinomas and the PSTT, demonstrating functional homology between these tumors despite some ultrastructural differences. These results demonstrate ultrastructural features of trophoblastic cells that correlate with the morphologic diversity seen in these tumors by light microscopy. Furthermore, the comparisons suggest that the PSTT is composed of a distinct form of intermediate trophoblast that appears to reflect its origin from the extravillous trophoblast.     

Interleukin-12 inhibits cell invasion in choriocarcinoma

Gestational trophoblastic disease (GTD) is a unique disease that arises from allografting of the conceptus, and has a characteristic morphology and biological behavior. It encompasses a spectrum of interrelated diseases, including hydatidiform mole, invasive mole, choriocarcinoma and placental-site trophoblastic tumor, but its pathogenesis remains unrevealed. Particularly, choriocarcinoma is a highly malignant tumor with poor prognosis. In this study, we cultured the human choriocarcinoma cell line JEG-3 in vitro. After treating the cells with different doses of interleukin (IL)-12, the cell invasion was observed. We also detected the expression of matrix metalloproteinases (MMP)-9 and tissue inhibitors of metalloproteinases (TIMP)-1 and the cell cycle of JEG-3 cells. Our data indicated that IL-12 inhibits cell invasion in a dose- and time-dependent manner through regulating the expression of MMP-9 and TIMP-1. In addition, treatment with IL-12 redistributes the phases of the cell cycle in JEG-3 cells. These findings suggest an antitumor role of IL-12 in choriocarcinoma, with far reaching possibilities for understanding the mechanisms of IL-12.     

Leptin modulates extracellular matrix molecules and metalloproteinases: possible implications for trophoblast invasion

Leptin is a circulating hormone which plays an important role in the regulation of energy balance, haemopoiesis and reproduction. Leptin and its receptor (leptin-R) are localized in human placental tissue but their function is not known. In this study we have investigated the expression of leptin and leptin-R in the human placenta with particular attention to extravillous cytotrophoblastic cell islands and cell columns which play a pivotal role in trophoblast invasion and placental growth. We demonstrate that leptin-R immunoreactivity shows a strong expression in the distal extravillous cytotrophoblastic cells of cell columns invading the basal plate, whereas leptin expression is homogeneously expressed in all the cellular components of cell columns. Since the invasive ability of the distally located extravillous cytotrophoblast of cell columns is known to be regulated by a variety of proteases and some extracellular matrix molecules, we tested the influence of leptin on the in-vitro production of matrix metalloproteinase (MMP)-2, MMP-9 and fetal fibronectin (fFN) by cytotrophoblastic cells. We demonstrate that leptin increases, in a dose-dependent manner, the secretion of immunoreactive MMP-2 and fFN and enhances the activity of MMP-9 in cultured cytotrophoblastic cells. Our results suggest that leptin and leptin-R could have a role in the invasive processes of the extravillous cytotrophoblastic cells by modulating the expression of MMPs. In addition, these results provide a foundation for studying pathological conditions characterized by insufficient or excessive trophoblast invasion.     

Gestational trophoblastic tumours and non-neoplastic trophoblastic lesions: morphology and immunocytochemistry to refine the diagnosis

Gestational trophoblastic disease (GTD) is generally subclassified into hydatidiform moles (HM), Gestational trophoblastic tumours (GTTs) and non-neoplastic trophoblastic lesions. GTT represent a spectrum of neoplasms that originate from the extravillous trophoblast and have variable malignant potential. These include choriocarcinoma (CC), Placental site trophoblastic tumour (PSTT) and Epitheloid trophoblastic tumour (ETT). Among tumour like conditions exaggerated placental site reaction (EPSR) and placental site nodule (s)/plaque (s) are included. The morphological appearances of GTT can be mimicked both by non-malignant tumour-like conditions and also non-gestational tumours with trophoblastic differentiation, adding to the diagnostic dilemma of these already rare tumours. GTT have a favourable prognosis and better response to specific chemotherapeutic regimens when compared to non-gestational malignant genital tract neoplasms, and thus their recognition is important. This article discusses the morphological appearances and immunocytochemistry of these rare tumours along with recent developments in the form of targeted immunotherapy.     

Gestationsbedingte Trophoblasterkrankungen

The differential diagnosis of villous forms of gestational trophoblastic disease (GTD) includes hydropic abortion, complete and partial hytatidiform mole and placental mesenchymal dysplasia. In addition to histologic criteria, p57^KIP2 immunohistochemistry might be helpful. Choriocarcinoma represents the most immature form of GTD. This and downregulation of HSP-27 might contribute to the high chemosensitivity, compared to placental site (PSTT) and epitheloid trophoblastic tumor (ETT). Within the differential diagnosis of the non-villous forms of GTD an algorithmic approach of immunohistochemistry is very helpful. With an incidence of 1.6% of all abortions within the first trimester the exaggerated placental site reaction (EPS) is rare. There is no molecular indication that the EPS represents a precursor lesion of PSTT. The morphologic prediction of the behaviour of PSTT is not well established. Factors which might be associated with adverse outcome are age >35 years, interval since last pregnancy >2 years, growth outside the uterus, deep myometrial invasion, destructive growth, extensive coagulative necrosis, presence of cells with clear cytoplasm, high mitotic rate and a Ki-67 labeling index >50%. Recent molecular data suggest a neoplastic transformation of (cyto-) trophoblastic stem cells, within the pathogenesis of (non-villous) GTD. The detection of target molecules for a targeted therpapy is currently irrelevant.     

The pathology of gestational trophoblastic disease: recent advances

When inundated with numerous specimens of products of conception as the consequence of miscarriage, it is all too easy for histopathologists to forget that the biology of trophoblast and the events of early placental implantation continue to fascinate because of the inherently invasive properties of the non-villous (extravillous) trophoblast. However, unlike the invasion of a malignant tumour, the invasion of trophoblast is controlled. The failure of adequate conversion of maternal uteroplacental arteries is a major pathogenetic phenomenon of important disorders of pregnancy including pre-eclampsia. However, it is in the field of gestational trophoblastic disease that diagnostic acumen is most called for. There are several problematic areas that give rise to diagnostic error; e.g., the diagnosis of early complete mole as partial mole, the over-diagnosis of hydatidiform mole in tubal pregnancy and the diagnosis of placental site non-villous trophoblast as placental site trophoblastic tumour or choriocarcinoma, particularly if associated with atypia, as frequently observed in complete mole. The chorionic villi of early diploid complete mole show characteristic features of villous profile, stromal mucin and stromal nuclear debris. The distinction between complete mole and triploid partial mole can be facilitated by ploidy analysis and immunohistochemistry for the product of the paternally imprinted, maternally expressed gene, p57kip2. Persistent trophoblastic disease (PTD) is a clinical not a histopathological diagnosis and the role of the histopathologist once a diagnosis of PTD has been made is limited. Invasive mole and choriocarcinoma are encompassed by PTD. Tumours of the non-villous trophoblast are placental site trophoblastic tumour and the more recently recognised epithelioid trophoblastic tumour. The role of immunohistochemistry in the elucidation of trophoblastic lesions is discussed pragmatically.     

Effects of Tumor Necrosis Factor-Alpha on Human Trophoblast Cell Adhesion and Motility

PROBLEM: Adhesive interaction between trophoblast cells and uterine endometrial basement membrane is one of the critical processes in embryo implantation. This interaction is directly or indirectly regulated by hormones, growth factors, and cytokines. Since tumor necrosis factor-alpha (TNF-α) is synthesized by both decidual and trophoblast cells, we hypothesized that TNF-α may play a regulatory role in trophoblast cell invasion. To test this hypothesis, we have used in vitro models to determine the effect of TNF-α on human trophoblast cell adhesion and motility, two major steps in trophoblast invasion. METHODS: The effect of TNF-α on the motility of extended-lifespan first trimester trophoblasts (HTR) and JEG-3 choriocarcinoma cells was tested using the phagokinetic track motility assay. An in vitro adhesion assay was used to determine the effect of TNF-α on the adhesion of HTR and JEG-3 cells to laminin, a major basement membrane component. In addition, the effect of TNF-α on the surface expression of the laminin receptor β1 integrin subunit was examined using flow cytometry. RESULTS: HTR or JEG-3 cells were strongly adherent to laminin which was not significantly altered by TNF-α treatment. We also measured the effect of TNF-α on the surface expression of β1 integrin on HTR and JEG-3 cells; no difference was observed between control and treatment groups. Interestingly, the motility of both HTR and choriocarcinoma JEG-3 cells was significantly inhibited by TNF-α. CONCLUSIONS: The role of TNF-α in human embryo implantation is currently unknown. Our data demonstrate that TNF-α does not alter trophoblast cell adhesion to laminin, but significantly inhibits trophoblast cell motility in vitro, suggesting that TNF-α may play a regulatory role in trophoblast cell invasion.     

Thrombin receptors and protease-activated receptor-2 in human placentation: receptor activation mediates extravillous trophoblast invasion in vitro

Proteolysis of the thrombin receptor, protease activated receptor-1 (PAR1), may enhance normal and pathological cellular invasion, and indirect evidence suggests that activation of PAR1 expressed by invasive extravillous trophoblasts (EVTs) influences human placentation. Here we describe PAR1, PAR2, and PAR3 protein distribution in the developing human placenta and implicate PAR1 and PAR2 activation in functions central to EVT invasion. PAR1, PAR2, and PAR3 are expressed in cultured 8- to 13-week-old EVTs, and in situ in 18- to 20-week-old placental syncytiotrophoblasts and invasive trophoblasts. Thrombin, but not the PAR2 agonist peptide SLIGKV, inhibited proliferation in cultured EVTs, although both agonists stimulated phosphoinositide hydrolysis and EVT invasion through Matrigel barriers. Thrombin-induced phosphoinositide hydrolysis was completely inhibited and the thrombin effect on proliferation was prevented when PAR1 cleavage was first blocked with specific monoclonal antibodies, indicating that PAR1 is the predominant thrombin receptor on EVTs. Together these results support a role for PAR1, and potentially PAR2 and PAR3 in the invasive phase of human placentation.     

P57kip2 immunohistochemical expression and ultrastructural findings of gestational trophoblastic disease and related disorders

Gestational trophoblastic disease (GTD) is a unique spectrum of diseases ranging from complete hydatidiform mole (CHM), partial hydatidiform mole (PHM), and invasive mole (IM) to choriocarcinoma (CC). Placental site trophoblastic tumor (PSTT) and epithelioid trophoblastic tumor (ETT) have been classified as related disorders. Mesenchymal dysplasia (MD) may be misdiagnosed as PHM; however, it is said to have a quite different histogenesis from PHM. P57kip2 is the protein product of a paternally imprinted or maternal gene that inhibits cyclin-dependent kinases (CDK), thus serving to inhibit cell proliferation and to suppress tumor growth. Its lack of expression in trophoblastic disease plays a role in its abnormal proliferation and differentiation. In this study, P57kip2 immunostaining was absent in the trophoblastic layers of CHM and was positive in the trophoblast layer of nonmolar villi and MD. Ultrastructure of complete molar cystic villi showed tree-like branching of microvillous processes and intracytoplasmic lacunae without capillaries in the stroma, whereas MD contained many newly formed blood vessels and collagen. Also, large lacunae with microvilli and polymorphic nuclei of syncytiotrophoblast cells with well-developed organelles were observed in IM. Lung ETT following CHM and normal deliveries showed two types of large mononuclear cells and binuclear cells with abundant organelles and bundles of intermediate-type filaments in the stroma.