Defective pericyte recruitment of villous stromal vessels as the possible etiologic cause of hydropic change in complete hydatidiform mole.

The pathogenetic mechanism underlying the hydropic change in complete hydatidiform moles (CHMs) is poorly understood. A growing body of data suggests that pericytes play a role in vascular maturation. Since maturation of villous stromal vessels in CHMs is markedly impaired at early stages, we postulated that a defect in pericytes around stromal vessels in chorionic villi might cause vascular immaturity and subsequent hydropic change. To investigate this, we examined several markers of pericytes, namely, α-smooth muscle actin (α-SMA), platelet-derived growth factor receptor-ß (PDGFR-ß), and desmin, in 61 normally developing placentas and 41 CHMs with gestational ages of 4-12 weeks. The ultrastructure of villous stromal vessels was also examined. Mature blood vessels from normal placentas show patent vascular lumens and formed hematopoietic components in the villous stroma. α-SMA and PDGFR-ß expression in the villous stroma gradually increased and extended from the chorionic plate to peripheral villous branches. The labeled cells formed a reticular network in the villous stroma and, after week 7, encircled villous stromal vessels. In comparison, α-SMA and PDGFR-ß expression in the villous stroma and stromal vessels of CHMs was significantly lower (p<0.05). Ultrastructurally, endothelial cells in villous stromal vessels in normal placentas were consistently attached by pericytes after week 7 when the vessels formed distinct lumen, whereas the villous stromal vessels in CHMs consisted of linear chains of endothelial cells, often disclosing primitive clefts without hematopoietic cells inside, and neither pericytes nor basal lamina surrounded the endothelial cells at any gestational age studied. This suggests that pericytes recruitment around villous stromal vessels is defective in CHMs and links to the persistent vascular immaturity of the villous stroma in CHMs, which in turns leads to hydropic villi.

Partial hydatidiform mole with extensive angiomatoid vessel configuration in a first trimester miscarriage.

We report a first trimester miscarriage (9 wk gestation) with a macroscopic grape-like aspect due to extensive angiomatoid changes with widened communicating thin-walled villous vessels. Fluorescence in situ hybridization analysis and microsatellite analysis revealed a diandric triploidy of the trophoblastic tissue, so this miscarriage is indeed a genetic partial hydatidiform mole. This is remarkable since the typical morphologic hallmarks of partial hydatidiform mole, especially enhanced trophoblastic proliferation and marked villous cistern formation, were not prominent. The finding of extensive angiomatoid morphology is to our knowledge an undescribed morphology of an early partial hydatidiform mole. It serves as an example of the morphologic variability of this probably underestimated condition that has a slightly elevated risk for the development of gestational trophoblastic disease.

Placental mesenchymal dysplasia presenting as a twin gestation with complete molar pregnancy.

BACKGROUND: Placental mesenchymal dysplasia is a rare abnormality characterized by placentomegaly, grapelike cystic vesicles, and villous hyperplasia. The clinical and ultrasonographic presentation may mimic molar pregnancy, provoking incorrect diagnoses and unnecessary therapeutic interventions. CASE: A 36-year-old nulliparous woman presented for prenatal ultrasonography that indicated the presence of one gestational sac containing both fetus and cystic mass, concerning for partial molar pregnancy. Amniocentesis returned a 46,XX karyotype, suggesting a twin gestation with complete mole. The patient was monitored closely and, because of fetal growth restriction, was induced successfully at term and delivered a healthy newborn. Histopathologic findings of the placenta were consistent with placental mesenchymal dysplasia. CONCLUSION: Although placental mesenchymal dysplasia is often confused with molar pregnancy, it is important to consider both in a differential to avoid inappropriate treatments.

Analysis of the vascular profile and CD99 protein expression in the partial and complete hydatidiform moles using quantitative CD34 immunohistochemistry.

BACKGROUND: Hydatidiform mole is a gestational trophoblastic disease with two different types: complete (CHM) and partial hydatidiform moles (PHM). The villous stroma of CHM is avascular or contains primitive endothelial-lined vascular elements. CD99 is a leukocyte antigen expressed in both normal and neoplastic tissue. OBJECTIVES: To examine the expression of CD99 and vascular profile in PHM and CHM compared to first trimester pregnancy termination (TOP). MATERIALS AND METHODS: Fifty trophoblastic tissue specimens were immunostained using monoclonal antibodies decorating CD99 and CD34 antigens (vasculogenesis). CD99 expression and the vascular parameters were scored. RESULTS: In CHM and PHM, the number of blood vessels with distinct lumens in the villous stroma (centrally and peripherally located) was significantly reduced (p<0.05), compared to TOM. In CHM, the number of the centrally located hemangiogenetic cords was higher compared to TOP. No statistically significant differences were found between CHM and PHM. In chorionic villi of TOP, a strong CD99 reactivity was seen in the endothelial, decidual, fibroblastic and in trophoblastic cells (syncytiotrophoblasts and cytotrophoblasts). Weak to virtually absent CD99 reactivity was seen in the trophoblastic cells of chorionic villi with molar changes. CONCLUSIONS: Vasculogenesis can be initiated in the molar pregnancies despite the absence of embryos or maternal derived chromosomes. CD99 may have a possible role in the development of molar changes.

Vascularization and expression of angiogenic factors in partial and complete molar pregnancies.

OBJECTIVE: To determine the microvessel density (MVD) at the implantation site of normal placenta (NP) and molar pregnancies and to correlate MVD with clinical data and underlying angiogenic factors. STUDY DESIGN: Immunolocalization of CD31, vascular endothelial growth factor and angiopoietin 1 and 2 were performed on NPs, nonpersistent partial moles, persistent partial moles (PPM), nonpersistent complete moles and persistent complete moles (PCM). RESULTS: Significant differences were identified in the MVD between NP and complete mole (CM), and PM and CM (p < 0.001 and p < 0.035, respectively). MVD in PPM and PCM was significantly higher (p = 0.036 and p < 0.001, respectively) when compared to NP. MVD > 100 per high-power field was associated with an increased risk of persistence (p < 0.04). MVD showed a strong correlation with immediate postevacuation hCG levels (p < 0.03). Angiopoietin 2 staining was more heterogeneous, with lower overall expression in molar pregnancies as compared to more homogeneous expression in NP (p < 0.05). CONCLUSION: MVD is highly correlated with hCG levels, suggesting that hCG may act as an angiogenic factor during implantation of molar pregnancy. MVD at the implantation site may be associated with excessive trophoblastic proliferation or reflect high hCG levels, which places patients at increased risk of persistent neoplasia.

The architecture of first trimester chorionic villous vascularization: a confocal laser scanning microscopical study.

BACKGROUND: The aim of this study was to investigate normal chorionic villous vascularization using CD31 immunofluorescence and confocal laser scanning microscopy (CLSM) to elucidate the spatial arrangement in terms of connections between vessels and cords and their branching patterns compared to deficient chorionic villous vascularization in complicated pregnancies. METHODS: A descriptive morphologic study using CLSM after CD31 immunofluorescence staining of placental biopsies from normal pregnancies (n = 20), complete hydatidiform molar pregnancies (CHMs; n = 3) and empty sacs (n = 3), with a well documented gestational age (GA). RESULTS: In this three-dimensional study, first trimester chorionic villi were occupied by a complex network of mainly cords with redundant connections as early as 5(+5) weeks GA. With increasing GA cords transform into vessels. From about 9 weeks GA onwards, vascular development is characterized by the presence of two large vessels located centrally and surrounded by and connected to a capillary network. In first trimester CHM and empty sacs, we observed a primitive network of mainly cords. CONCLUSIONS: This first visualization of the spatio-temporal patterns of blood vessel formation in placental villi is characterized by the development of the vasculosyncytial membrane from a complex network of cords and can be regarded as the placental development before it becomes functional at the end of organogenesis.

Diagnostic and pathogenetic significance of increased stromal apoptosis and incomplete vasculogenesis in complete hydatidiform moles in very early pregnancy periods.

Hydropic swelling, trophoblastic proliferation, and stromal avascularity of chorionic villi are the key features of advanced cases of complete hydatidiform moles (CHMs). Recently, however, the use of high-resolution ultrasonography has enabled earlier detection of CHMs, and these show previously unrecognized histologic features such as numerous immature vascular networks, nonhydropic hypercellular stroma, and frequent karyorrhexis in the villous stroma. To determine whether stromal vasculogenesis is affected in CHMs of very early pregnancy period (VECM), we compared the number of mature and immature blood vessels and their precursors in the villous stroma and counted the rates of stromal apoptosis and proliferation, as defined by immunopositivity for cleaved caspase-3 and Ki-67, in 63 cases of VECM, 11 cases of partial hydatidiform mole (VEPM), and 10 samples of normal placental tissue (NP) before the 13th gestational week. Using antibody to CD31, we found that the number of mature blood vessels with distinct lumen was significantly reduced in both VECM and VEPM compared with NP (P<0.001), but the number of CD31-positive primitive stromal cells or immature vascular networks without lumen did not differ significantly among the three groups. Stromal apoptotic rate was significantly higher in VECM than in VEPM or NP (P<0.001), which was very useful in differential diagnosis. Our results suggest that complete vasculogenic differentiation is significantly retarded in VECM due to increased apoptosis in the precursor components of blood vessels. It may result in a lack of vascular drainage and cause progressive accumulation of vesicular fluid in the later gestational period.

Elucidation of vascular structure of molar villi in complete hydatidiform mole by CD-34 antibody.

Vasculature was examined immunohistochemically in the villous stroma in 22 cases of complete hydatidiform mole (CHM). Only antibody CD-34 was able to detect the vasculature. Serial thin and thick sections and squashed preparations of molar villi were stained by CD-34, and sequential photographs of the vasculature were taken and projected on paper, and the vasculature was described and reconstructed. In the stroma of almost all molar villi examined, vessels were found, but their density and structure varied greatly in each molar villus even in the same CHM, and the vessels were irregular in diameter. In fully distended molar villi the vessels often became narrow, continuing like a broken line but eventually vanishing. Generally the density of the vessels was inversely proportional to the grade of the swelling of villi. The vessels sometimes passed through two adjacent molar vesicles. No significant differences in vasculature were found in molar villi at different gestational ages.

Numerous vessels detected by CD34 in the villous stroma of complete hydatidiform moles.

It has been considered that the villous stroma of complete hydatidiform moles (CHMs) is usually avascular. Vessels would normally form if embryogenesis had occurred. But judging by the structural maturity of molar villi, it was suspected that they must contain a considerable number of blood vessels and an attempt was made to demonstrate their presence. It has been shown previously that the vascular endothelial cell markers factor VIII related antigen (FVIII-RAg), Ulex europaeus 1 agglutinin (UEA-1) and CD31 were of no use in demonstrating the vessels in molar villi. A monoclonal antibody, QBEND/10, raised against the CD34 antigen in human endothelial cell membranes and hemopoietic progenitor cells, was selected to test its use as a marker of villous vascular endothelial cells in CHMs. On immunohistochemical analysis, numerous blood vessels were found using CD34 antibody in the stroma of CHMs, and the numbers corresponded to those found in normal villi of gestational age 8-12 weeks. Moreover, the luminal free surface of all vascular endothelial cells was so specifically delineated that it permitted the identification of vessels not apparent on hematoxylin- and eosin-stained sections; other stromal cells and trophoblast were not labeled.

Serial color Doppler flow of uterine vasculature combined with serum beta-hCG measurements for improved monitoring of patients with gestational trophoblastic disease. A preliminary report.

Weekly serum beta-hCG measurements and transvaginal ultrasound scans coupled with color Doppler flow were performed on 8 patients with hydatidiform mole. Two patients later developed persistent trophoblastic disease, necessitating chemotherapy. The correlation coefficients between Doppler flow indices, systolic-diastolic (S/D) ratio and pulsatility index (PI) with log beta-hCG were -0.96 and -0.97, respectively. The weekly S/D and PI indices were plotted on an individual curve. Only the 2 patients who developed persistent gestational trophoblastic disease had PI index levels of < or = 1.5 as early as 2 weeks after molar evacuation. At that stage their serum beta-hCG levels were not different from some of the other patients. In this preliminary report, the regression of the disease could be reliably assessed by observing the changes in low resistance flow which paralleled the gradual decrements in serial beta-hCG levels. Thus, the contribution of this noninvasive imaging technique encourages the authors to further investigate Doppler flow monitoring among a larger sample of patients suffering from various gestational trophoblastic diseases.

Doppler assessment of the uterine circulation and the clinical behaviour of gestational trophoblastic tumours requiring chemotherapy.

The haemodynamics of the uterine arteries and myometrium were assessed using Doppler ultrasound in forty consecutive patients requiring treatment for invasive mole and choriocarcinoma. The investigations were performed prior to the commencement of chemotherapy and the subjects followed prospectively. The Doppler waveforms from the uterine arteries were analysed using the pulsatility index. It was found that patients with a pulsatility index of 1.1 or less were significantly more likely to develop drug resistance than those with a higher value (P < 0.04). There was no significant association between the pulsatility index and metastatic disease or uterine bleeding. Five out of eight patients who developed drug resistance could have avoided initial inadequate treatment if the Doppler findings were included in the scoring system for selecting chemotherapy for these tumours. It can be concluded that assessment of the uterine arteries using the pulsatility index prior to the treatment of patients with invasive mole and choriocarcinoma is of help in predicting those who will develop drug resistance.

Intratumoral blood flow: evaluation with color Doppler echography.

Blood flow in several types of tumors (two hepatomas, two hemangiomas, two renal cell carcinomas, one hydatidiform mole, and five invasive moles) was assessed with real-time two-dimensional color Doppler echography (ultrasound). In one of the hepatomas and all five of the invasive moles (but not in the hydatidiform mole or in either of the hemangiomas), the intratumoral flow was demonstrated with color Doppler echography, correlating well with the angiographic or dynamic computed tomographic findings. In the invasive moles, rapid blood flow was seen within the hypoechoic zone of the tumor. On follow-up study of four of the invasive moles, disappearance of the hypoechoic area due to blood flow was observed when chemotherapy was successful. Trophoblastic disease is considered to be the best application for color Doppler echography because it provides accurate evaluation of residual tumor after chemotherapy.