Chorangioma with trophoblastic proliferation

Only two examples of the entity of chorangiocarcinoma, in which there is a proliferation of both the vascular and epithelial components of the placental villi, have been reported in the literature. To test the hypothesis that chorangiocarcinomas are actually more common than implied by the literature, histological sections of chorangiomas were reviewed. Syncytiotrophoblast and cytotrophoblast proliferation, with nuclear atypia, similar to that found in trophoblastic neoplasia, were seen in 15 of 23 cases. Thus, 65% of chorangiomas fulfilled the diagnostic criteria to warrant re-assignment as "chorangiocarcinoma". The proliferation index of the cytotrophoblast in the tumor as measured by MIB-1 (Ki-67) immunostaining was significantly higher in "chorangiocarcinoma" than chorangioma (35.4% vs 15.7%, P<0.02). The following factors had no relationship to the presence or absence of trophoblastic proliferation: vascularity, cellularity, infarction, size or location of the chorangioma, or age of the patient. Five of the 15 chorangiomas with trophoblastic proliferation were of the chorangiomatosis variety. No formal follow-up was performed, as this was a retrospective study, but there is no recorded case of persistent gestational trophoblastic disease in this cohort, although one woman with "chorangiocarcinoma" had a history of previous hydatidiform molar pregnancies. An apparently benign clinical course is seen. These lesions, best described as chorangiomas with trophoblastic proliferation, are more common than suggested by the rarity of reported cases.     

Complete hydatidiform mole and normal live birth: a novel case of confined placental mosaicism: case report

Hydatidiform molar change, characterized by abnormal fetoplacental development and placental villous trophoblast hyperplasia, results from genetically abnormal conception, in which there is an excess of paternally derived genetic material. The majority of pregnancies in which molar change has been reported in association with a live fetus represent dizygotic twin pregnancies in which one fertilization results in a complete hydatidiform mole (CM) and the other a normal co-twin. In such cases, there is usually a clear distinction, both sonographically and pathologically, between the molar and non-molar regions of the placenta. We present a singleton pregnancy, with diffuse placental molar change detected prenatally, which resulted in a chromosomally and phenotypically normal female infant at term. Pathological examination revealed the presence of intermixed populations of morphologically normal chorionic villi and villi with the characteristics of CM. Studies of genetic polymorphisms demonstrated that the CM, normal villi and fetus were all derived from the same sperm; the fetus was diploid and biparental whereas the areas of pathological CM were androgenetic and monospermic. We believe this represents the first well-documented case of apparent confined placental mosaicism involving CM and a coexisting normal fetus, which has presumably arisen following mitotic abnormalities in the early post-fertilization period.     

Complete hydatidiform mole in twin pregnancy

Six cases of hydatidiform mole associated with normal chorionic villi and a normal embryo/fetus (in five cases) were investigated with interphase cytogenetic and DNA cytometric analyses for diagnostic purposes. DNA probes specific for the pericentromeric regions of chromosomes 1 and X and for the long arm of chromosome Y were used. In four cases a dizygotic twin pregnancy could be proven. In these cases, the histologically normal chorionic villi showed an XY DNA-diploid pattern, consistent with a normal male conceptus, and the molar chorionic villi a XX pattern. In the other two cases an identical sex chromosomal pattern was found in the normal and in the molar villi (XX/XX and XY/XY respectively). In all six cases the molar placental tissues showed prominent trophoblastic hyperplasia with DNA-polyploidy, consistent with a complete hydatidiform mole. In two cases persistent gestational trophoblastic disease developed. It is emphasized that twin pregnancies composed of a normal conceptus and a complete mole have a relatively high risk for the development of persistent trophoblastic disease and therefore, should be carefully differentiated from triploid partial moles with a relatively low risk of persistent gestational trophoblastic disease. These case reports indicate that additional interphase cytogenetic and DNA cytometric analyses are useful in this differential diagnosis.     

Angioneogenesis in pre-eclamptic placentae

The ultrastructural patterns of new capillary formation in chorionic villi from placentae in severe pre-eclampsia were compared with those from placentae of normal early and term pregnancies. In pre-eclamptic placentae, syncytial knots were more frequent than that in normal term placentae and were surrounded by newly-formed villi. Newly-formed capillary vessels in severe pre-eclamptic placentae protruded from the original vessels beneath the trophoblasts forming syncytial knots. Their lumens were narrow and lined with thin endothelial cells containing abundant intermediate filaments actively secreting tropocollagen into the stroma. Compared to villi from normal early pregnancies, newly-formed villi in pre-eclampsia appeared to lack Langhans cells in some regions where connective tissue with blood vessels proliferated and seemed to be penetrating the trophoblasts. Even when complete, the capillaries of villi in severe pre-eclamptic placentae may not be able to exchange materials between mother and fetus.     

Cytoskeletal proteins in chronic villitis of unestablished etiology.

Cytoskeletal proteins (i.e., cytokeratins, vimentin, actin, and desmin) are normally present in the placental chorionic villi and are related to the maintenance of the villous shape, and to the ability of the villi to contract and permit a normal blood flow. In areas of villitis of unestablished etiology, the normal reactivity of these proteins in the villous core around fetal stem vessels disappears, and an increased number of cytokeratin positive cells is identified. The vascular damage in stem villi with villitis could develop ischemia in the villous tree promoting cytotrophoblast proliferation. Increased numbers of these areas could be related with the appearance of abnormal pregnancies.     

Vasculogenesis in early human placental villi: an ultrastructural study

In this study we examined the chorionic villi of 5 normal human placentas at 12–14 weeks of gestation ultrastructurally with regard to differentiation of the vascular components. The aim of the present report is to discuss the factors influencing vasculogenesis (in situ formation of blood vessels) at the ultrastructural level.

Our observations have led us to think that the cytotrophoblast influences vasculogenesis in human chorionic villi. Mesenchymal-preendothelial cell groups were always found in very close association with the cytotrophoblast at the periphery of the villi, forming blood vessels. The cytotrophoblast probably attracts mesenchymal cells towards the margin of the villi by secreting vascular endothelial growth factor (VEGF). Once cells attach to the trophoblastic basement membrane they begin to differentiate into endothelial cells. This close structural relation between two cell types (cytotrophoblast and mesenchymal cells) may not be the only mechanism controlling vasculogenesis, but it seems to be one of the factors influencing the differentiation of mesenchymal cells into the endothelial cells of blood vessels in early human chorionic villi.     

Placental vascular anomaly with diffuse mesenchymal stem villous hyperplasia. A new clinico-pathological entity?

Diffuse mesenchymal hyperplasia of placental stem villi produces a pathological increase of placental volume, gives images of partial hydatidiform mola on ultrasound examination and is associated with elevated levels of alpha feto-protein. On gross examination, the placenta is enlarged, the vessels on the fetal plate show aneurysmal and varicose dilatations, and the stem villi appear as distinct, semitranslucent lobulated structures. At microscopy level, stem villi show excessive proliferation of mesenchymatous tissue with foci of myxoid degeneration and large macrophages containing alcian blue positive material within cytoplasmic vacuoles. Involved areas show blood vessels with abnormally thin walls, which are negative to factor VIII and alpha feto-protein immunohistochemical reactions. Pathological trophoblastic proliferation or stromal trophoblastic inclusions are not part of this condition. Although there is a clear predominance of a female genotype in this cases, the true sex incidence in placental vascular anomalies with diffuse mesenchymal stem villus hyperplasia has yet to be defined.     

Morphology of the placenta in fetal I-cell disease

Placentas were studied from three interrupted pregnancies of a mother whose first live-born child had I-cell disease (mucolipidosis II). I-cell disease of the fetus was shown by investigation of the amniotic fluid, fetal cells and the aborted fetus in two pregnancies, but in the third case placenta was the only available product of conception. In every placenta extensive vacuolization of the syncytiotrophoblastic layer of the chorionic villi and chorionic mesenchymal cells was found. In electron microscopy the inclusions were identical to those of other tissues in I-cell disease. The importance of histological study of placenta in unexplained spontaneous abortions needs to be emphasized, since this may be the only way of detecting new cases of lysosomal storage diseases.     

Twin pregnancy with both complete hydatiform mole and coexistent alive fetus: report of a non-antenatal diagnosed case

Twin pregnancy with both complete hydatiform mole and coexistent fetus is a rare situation and a challenging diagnosis. We report an unusual case of twin pregnancy with complete mole diagnosed after pathological examination of the placenta. A 30-year-old woman, 14 weeks gestation, presented with vaginal bleeding. The abdominal ultrasound examination revealed an heterogeneous aspect of inferior placenta, which was interpreted as a hematoma, and, a multilacunar placental aspect with an oligoamnios respectively at initial follow-up and 22 weeks gestation. The karyotype from chorionic villi was normal (46 XY). At 25 weeks, after a spontaneous abortion, she delivered a 950g newborn who died quickly. On placental gross examination two distinct but connected masses were identified: one exhibited a normal placental aspect and the other vesicular villi with necrotic and hemorrhagic fragments. On microscopic examination, the normal placenta showed well-developed chorionic villi and the multicystic placenta showed molar villi. Immunohistochemical study and fluorescence in situ hybridization confirmed a complete hydatiform mole. No persistent gestational trophoblastic neoplasia was observed during the follow-up.     

An ultrastructural study of early chorionic villus formation in the marmoset monkey (Callithrix jacchus)

Summary The ultrastructural morphology of developing chorionic villi in the marmoset monkey (Callithrix jacchus) placenta was studied in pregnant monkeys at known time intervals after ovulation. In samples obtained at 45 days after ovulation the mesoderm, which consists of primitive foetal blood vessels, is seen to extend down into cytotrophoblast columns. Syncytiotrophoblast completely surrounds maternal blood vessels and both basal laminae and endothelial cells of maternal origin show signs of disorganisation and degradation. Syncytiotrophoblast is first observed to breach the maternal circulation in samples collected from animals at 60 days after ovulation; this results in discrete haemochorial villi randomly distributed throughout the placental bed. Samples obtained at 80 days after ovulation and term placental samples (145 days after ovulation) exhibit tertiary haemochorial villi throughout the placenta, similar to those seen randomly distributed at 60 days after ovulation.     

Prenatal diagnosis and fetal pathology of aspartylglucosaminuria

The prenatal diagnosis of aspartylglucosaminuria (AGU), a lysosomal storage disorder of glycoprotein degradation, was made by demonstrating the deficiency of N-aspartylglucosaminidase on cultured cells from a midterm amniotic fluid sample. Four other amniotic fluid studies from at-risk pregnancies gave a normal or a heterozygote level of enzyme activity. These pregnancies have gone to term and the delivery of healthy babies. The pregnancy with the affected fetus was terminated and the prenatal diagnosis was verified by enzyme assays on cord blood lymphocytes, cultured cells from skin biopsy, and from placental villi. Electron microscopic evidence of lysosomal storage was seen in several organs of the fetus with the notable exception of the central nervous system. The undifferentiated mesenchymal fibroblasts particularly were heavily loaded with cytoplasmic inclusions in skin, liver, kidney, and placenta.     

Myocytes of chorionic vessels from placentas with meconium-associated vascular necrosis exhibit apoptotic markers

Meconium-associated vascular necrosis (MAVN) is a histological abnormality of human placental chorionic vessels that is associated with poor neonatal outcome. We tested the hypothesis that MAVN shows apoptosis in the walls of chorionic vessels. Archival placental specimens with MAVN (n = 5) were compared with specimens from uncomplicated pregnancies at term (n = 5) and from placentas with intense chorionic vasculitis associated with acute chorioamnionitis with (n = 5) or without (n = 5) a clinical history of meconium in the amniotic fluid. Sections from all placentas were processed by the TUNEL method, and 2 observers who were blinded to specimen diagnosis quantified the immunofluorescent TUNEL staining in both the amnion-facing and villous-facing walls of the larger chorionic vessels in each specimen. Compared with the other 3 groups, only the amnion-facing wall of chorionic vessels in MAVN showed a significantly greater number of apoptotic cells. This was verified by morphological criteria and caspase 3 staining. There were limited or no detectable TUNEL-stained cells in either the villous-facing walls of vessels in the MAVN specimens or in any of the vessels of the placentas from uncomplicated pregnancies. There was a negligible level of apoptosis in chorionic vessels of placentas with intense chorionic vasculitis, with or without meconium, despite the inflammatory response or presence of meconium. We conclude that apoptosis contributes to the pathophysiology of MAVN.     

Characteristics of histopathological and ultrastructural features of placental villi in pregnant Nepalese women

The placenta is an important functional unit for gas transfer between mother and fetus. The placental membrane, consisting of trophoblast layer interposed between maternal and fetal blood, plays an active role for intensity of respiration, but no morphological evidence has been documented. Until now, it has been reported that fetal growth retardation and increased fetal mortality rate usually could be seen at high altitude. In an attempt to find the cause of high perinatal mortality rate in Nepal, this study was undertaken to examine pathologically about 1000 Himalayan placentas obtained in Nepal and Tibet since 1977, and the results were compared with those of 5500 Japanese placentas at Saitama Medical School since 1990. In this study, characteristics of ultrastructural features of the Nepalese placental villi investigated in recent years are reported. (1) The gross characteristics of placental pathology in the Himalayan group were represented by marked subchorionic fibrin deposits and increased chorionic cysts in contrast to low incidence of intervillous thrombosis compared with those of the Japanese group. (2) As characteristics of histological findings of the placental villi between Himalayan and Japanese groups, the incidence of chorangiosis and chorangioma in the Himalayan group was significantly higher than that in the Japanese group. (3) Accompanying an increase of vasculosyncytial membrane (VSM) in the villi, thickness and separation of basement membrane of the syncytium in addition to increased apoptosis of syncytial cell nuclei were recognized. (4) As characteristic ultrastructural features of chorionic villi of Nepalese placentas, an increase of mitochondria and cystic formation of rough endoplasmic reticulum (rER), in addition to appearance of lamellar bodies similar to alveolar epithelial type II cell in organellae of the syncytium, were observed. These ultrastructural changes of the placental villous capillaries may be ascribed to hypevascularization caused by the chronic hypoxic state. It is, therefore, presumed that trophoblast cells may play an important role for gas transfer mecha-nism under such a hypoxic state at high altitude.     

Maternal Cells in Chorionic Villi From Placentae of Normal and Abnormal Human Pregnancies

PROBLEM: We asked if activated macrophages and CD4 positive T lymphocytes in placental chorionic villi with villitis were of maternal or fetal origin. METHOD: We employed a double antibody immunocytochemical technique on placental sections from three normal and four abnormal pregnancies with small-for-gestational-age infants. All studied placentae were mismatched for the maternal-fetal HLA-DRw 52 antigen. Areas of immunopathology were identified by using a monoclonal antibody to a monomorphic determinant on HLA-DR, and the origin of immunological cells in areas of immunopathology was identified by using a monoclonal antibody to a polymorphic determinant on HLA-DRw 52. RESULTS: We used a double antibody technique that employed monoclonal antibodies to HLA-DR and HLA-DRw 52 antigens and placentae that were mismatched for the maternal-fetal HLA-DRw 52 antigen. We found that the vast majority of immunological cells within villi with inflammation were of maternal origin. Quantitative studies showed that between 75 and 100% of the cells in normal as well as in abnormal pregnancies were of maternal origin, and that abnormal pregnancies had a significantly higher percentage of villi with maternal cellular infiltrates. CONCLUSION: Our data show unequivocally that cells in areas of placental immunopathology are predominantly of maternal origin, and that abnormal pregnancies are associated with significantly more villi containing immunological cells of maternal origin.     

Thy-1 differentiation protein and monocyte-derived cells during regeneration and aging of human placental villi.

PROBLEM: The classification of placental villi was reviewed, and regeneration of villous trees in mature human placentae was examined. METHOD OF STUDY: Expression of Thy-1 by placental fibroblasts and pericytes, and markers of endothelial cells and monocyte-derived cells were studied by immunohistochemistry and image analysis. RESULTS: Villous regeneration consists of: (i) dedifferentiation of mature ramuli into young stem villi producing mesenchymal villi; (ii) differentiation of mesenchymal villi into immature intermediate villi; and (iii) differentiation of immature intermediate villi into transitory intermediate villi, branching into the precursors of mature intermediate and terminal villi. These processes are associated with dedifferentiation and redifferentiation of placental monocyte-derived cells. Significant changes of Thy-1 expression by fibroblasts and pericytes accompany aging and degeneration, as well as regeneration of placental villi. CONCLUSIONS: Villous aging and degeneration in normal mature human placenta is compensated by regeneration of villous trees. Lack of villous regeneration may cause chronic fetal distress, due to the increasing demands of the growing fetus on the remaining terminal villi.     

Microvascular perturbations in human allografts: analogies in preeclamptic placentae.

The thromboresistance of endothelium is maintained as long as natural anticoagulant pathways are functionally present on endothelial plasma membranes. The principal anticoagulant pathways in human hearts and kidneys are thrombomodulin (TM) and heparan sulfate proteoglycan-antithrombin III (HSPG-ATIII). The downregulation of TM or the loss of ATIII is associated with fibrin deposition. This sequence of events occurs when stable allografts of hearts or kidneys become unstable or rejected. Human placentae do not contain the HSPG-ATIII natural anticoagulant pathway, but the TM system is uniformly represented on endothelium of normal chorionic villi. However, many villi in placentae from preeclamptic pregnancies contain thrombomodulin-negative endothelium, and these vessels contain fibrin thrombi. These thrombi compromise blood flow through the placental microcirculation and are associated with ischemic changes either with or without the presence of cellular infiltrates.     

Analysis of cultured chorionic villi in a case of osteogenesis imperfecta type II: implications for prenatal diagnosis

We examined collagens produced by cultured cells from skin, chorionic villi, and placental membranes of a 32 week fetus with osteogenesis imperfecta (OI) type II. We observed that skin fibroblasts synthesized two populations of pro alpha 1(I) chains of type I procollagen; one population was normal, while the other population had excessive post-translational modification. The thermal stability of helices containing the overmodified chains was reduced 1-2 degrees C. Most significantly, the cells cultured from chorionic villi produced type I collagen chains with the same electrophoretic abnormalities as the skin collagen. This suggests that chorionic villus sampling (CVS) is a means of prenatal diagnosis for families with a previous type II or type IV OI infant.     

Placentomegaly with massive hydrops of placental stem villi, diploid DNA content, and fetal omphaloceles: possible association with Beckwith-Wiedemann syndrome.

Marked placental hydrops is generally associated with hydatidiform mole. Diagnosis of hydatidiform mole requires both villous hydrops and trophoblast hyperplasia. This report describes four cases with massive hydrops of placental stem villi without associated trophoblast hyperplasia. All four had diploid DNA content by flow cytometry. Fetal omphalocele was present in three; and one had diagnostic Beckwith-Wiedemann syndrome (BWS). In two others, there were pathologic features suggestive of BWS. The fourth fetus had multiple anomalies by ultrasound; autopsy examination of the fragmented fetus failed to disclose additional pathology. The association of massive placental hydrops involving stem villi, fetal omphalocele, and diploid DNA content is unusual. These fetal and placental findings may suggest possible BWS in some cases and allow for antenatal diagnosis of affected fetuses, clinical evaluation of additional family members, and planning for neonatal care.     

First trimester development of human chorionic villous vascularization studied with CD34 immunohistochemistry

Normal chorionic villous vascularization is essential for the undisturbed development of pregnancy. Defective vasculogenesis may play a role in pathological pregnancy. To assess pathological chorionic villous vascularization, normal vascularization has to be defined first. Few data are available on this topic. The aim of this study was therefore to investigate normal chorionic villous vascularization in ultrasound-dated first trimester pregnancies from week 5 menstrual age to week 12 (n = 41), using quantitative CD34 immunohistochemistry. Two important processes in chorionic villous vascularization were quantitatively illustrated: (i) maturation, reflected by an increase of the total number of luminized vessels as opposed to non-luminized haemangioblastic cords and (ii) margination, due to a decrease of villous stromal area and an increase of total villous vascular area. The percentage of villous stromal area occupied by vascular elements (area difference %) increased from 0.7% in week 5-2.5% in week 10. Therefore, the area of the villous stroma occupied by vascular elements increases and the vessels are situated closer to the trophoblastic layer suitable for fetal-maternal exchange. There was also a trend in increased number of peripheral vessels (2.0 in week 5 to 4.6 in week 10), supporting both developmental mechanisms. In conclusion, in exactly dated normal human first trimester pregnancies, development of the chorionic villous vascular system seems to be mostly characterized by maturation of luminized vessels from primitive haemangioblastic cords, and margination to a situation of peripherally located vessels.