Molar gestations and hydropic abortions differentiated by p57 immunostaining

Pathological features of early pregnancy disorders in women living at high altitude in KSA

Objectives

Pregnancy at high altitudes is relatively challenging because of hypobaric hypoxia, which is associated with a smaller uterine artery diameter and diminished blood flow. Here, we investigated the histopathological characteristics of early pregnancy disorders among pregnant women living in a high-altitude region (approximately 2200 m above sea level).

Methods

This cross-sectional study used retrospective data collection from a single tertiary hospital in a high-altitude region in KSA. Age and histopathology were analyzed in 495 women diagnosed with early pregnancy disorders (mainly miscarriage) in 2018-2020.

Results

Approximately one-fifth of pregnancies in this high-altitude region were lost before 24 weeks' gestation, whereas 1150/6044 experienced miscarriage; 495 samples from those participants were sent for histopathological analysis. A total of 269 (54.34%) patients were younger than 35 years. Missed miscarriages accounted for 49.3% of miscarriages, followed by inevitable miscarriages (34.2%), which had a relatively higher frequency among mothers older than 35 years. The correlation between age and inevitable miscarriage was significant; ectopic pregnancy was diagnosed in 6.8%, molar pregnancy was detected in 6.26%, and blighted ovum was observed in 3.4%.

Conclusion

The miscarriage rate in this high-altitude region was 19% of all pregnancies. Approximately half of the affected women were in their 30s. Missed miscarriage cases were relatively high in this region. The percentage of molar pregnancy was higher than those reported in prior studies, thus suggesting a need for monitoring and genetic workup practices. Furthermore, studies involving a larger population at high altitudes will be crucial for further risk assessment in addition to national studies on women living at sea level.

Hydatidiform Moles: Ancillary Techniques to Refine Diagnosis

Context.—

Distinction of hydatidiform moles from nonmolar specimens and subclassification of hydatidiform moles as complete hydatidiform mole versus partial hydatidiform mole are important for clinical practice and investigational studies. Risk of persistent gestational trophoblastic disease and clinical management differ for these entities. Diagnosis based on morphology is subject to interobserver variability and remains problematic, even for experienced gynecologic pathologists.

Objectives.—

To explain how ancillary techniques target the unique genetic features of hydatidiform moles to establish diagnostic truth, highlight the issue of diagnostic reproducibility and importance of diagnostic accuracy, and illustrate use of p57 immunohistochemistry and polymerase chain reaction–based DNA genotyping for diagnosis.

Data Sources.—

Sources are the author's 10-year experience using ancillary techniques for the evaluation of potentially molar specimens in a large gynecologic pathology practice and the literature.

Conclusions.—

The unique genetics of complete hydatidiform moles (purely androgenetic), partial hydatidiform moles (diandric triploid), and nonmolar specimens (biparental, with allelic balance) allow for certain techniques, including immunohistochemical analysis of p57 expression (a paternally imprinted, maternally expressed gene) and genotyping, to refine diagnoses of hydatidiform moles. Although p57 immunostaining alone can identify complete hydatidiform moles, which lack p57 expression because of a lack of maternal DNA, this analysis does not distinguish partial hydatidiform moles from nonmolar specimens because both express p57 because of the presence of maternal DNA. Genotyping, which compares villous and decidual DNA patterns to determine the parental source and ratios of polymorphic alleles, distinguishes purely androgenetic complete hydatidiform moles from diandric triploid partial hydatidiform moles, and both of these from biparental nonmolar specimens. An algorithmic approach to diagnosis using these techniques is advocated.

Diagnostic Utility of Twist1, Ki-67, and E-Cadherin in Diagnosing Molar Gestations and Hydropic Abortions

OBJECTIVES

This study aims to assess whether the expression of Twist1, Ki-67, and E-cadherin can guide the differential diagnosis of complete hydatidiform mole (CHM), partial hydatidiform mole (PHM), and hydropic abortion (HA).

METHODS

Differential expression of Twist1, Ki-67, and E-cadherin was analyzed in gestational products from 55 cases of CHM, PHM, and HA using immunohistochemistry. Prior to analysis, the studied cases were confirmed for their diagnosis by flow cytometric assessment of DNA ploidy and p57 immunostaining.

RESULTS

Twist1 expression can distinguish CHM from PHM and HA with 100% sensitivity, 100%, specificity, 100% positive predictive value (PPV), and 100% negative predictive value (NPV). Furthermore, combined Ki-67 and E-cadherin expression could differentiate PHM and HA with 100% sensitivity, 93.3% specificity, 92.3% PPV, and 100% NPV.

CONCLUSIONS

Twist1 expression is a highly reliable marker for the diagnosis of CHM, where combined Ki-67 and E-cadherin immunoreactivity can distinguish PHM from nonmolar pregnancies.

Challenges in the Routine Praxis Diagnosis of Hydatidiform Mole: a Tertiary Health Center Experience

Introduction:

Hydatidiform moles (HM), presenting as complete (CHM) and partial (PHM) form, are rare pregnancy disorder. Diagnosis is based on clinical presentation, ultrasound imaging findings and pathological examination of products of conception. Protein p57, encoded by CKDN1C gene, is paternally imprinted and maternally expressed gene and provides quick insight in genetic basis of HM and allows distinction of CHM from all other conceptions. compare the preevacuational and pathohistological diagnosis with outcome of p57 immunostaining.

Material and methods:

All cases of HM diagnosed between January 2011 and December 2015 were included in this research. Maternal age, gestational age and input diagnosis data were recored. p57 immunostaining was performed in order to evaluate the diagnosis based on tissue slides examination.

Results:

There were 198 cases of histologically confirmed HM, 185 PHM, 12 CHM and one case of undefined HM. Mean maternal age in the CHM group was 24,7 and in the PHM group 26,9 years, with no significant differences among these two groups (p=0,27). For CHM mean gestational age was estimated at eight and for PHM 9,2 gestational weeks. Pregnant woman older than 40 years present significant earlier compared with younger woman (p<0,01), and those younger than 20 years tend to present at the beginning of the second trimester more often than older women (p<0,05). In the CHM group, 9 (75%) input diagnoses were mola in obs, and 3 (25%) of them were signed as abortion, unlike the PHM where 126 (67%) were qualified as abortion, 35 (19%) as blighted ovum, and 26 (14%) were suggestive for molar pregnancy. p57 immunostaining results confirmed all pathohistological diagnosis of CHM whereas 8% of PHM demonstrated divergent p57 expression.

Conclusion:

PHM, compared with CHM, represent a greater diagnostic challenge for both gynecologist and pathologist even when presenting in more advanced pregnancies.

Utilization of Chromogenic In Situ Hybridization to Assess Ploidy in the Diagnosis of Hydatidiform Mole

OBJECTIVES

Ploidy assessment is often required for the diagnosis of partial molar pregnancy. While fluorescence in situ hybridization has been shown to be effective, it is not available in many laboratories. We validated chromogenic in situ hybridization (CISH) for this purpose.

METHODS

CISH using probes to chromosomes 17 and 10 was performed on 20 POC cases with known cytogenetics to establish a reference percentage. This was then used to classify a randomized set of abnormal and normal cases.

RESULTS

An abnormal CISH cutoff of greater than 7% was established. All abnormal cases (six triploid and three tetraploid), 11 "normal" (46, XX or XY or undetectable abnormalities), and one trisomy 10 were all correctly classified by the assay.

CONCLUSIONS

CISH is a useful ancillary technique for the diagnosis of molar pregnancy. Its greater accessibility and ability to score even rare placental tissue in a background of maternal tissue offer advantages over other methods.

Characteristics of hydatidiform moles: analysis of a prospective series with p57 immunohistochemistry and molecular genotyping

Immunohistochemical analysis of cyclin-dependent kinase inhibitor 1C (CDKN1C, p57, Kip2) expression and molecular genotyping accurately classify hydatidiform moles into complete and partial types and distinguish these from non-molar specimens. Characteristics of a prospective series of all potentially molar specimens encountered in a large gynecologic pathology practice are summarized. Initially, all specimens were subjected to both analyses; this was later modified to triage cases for genotyping based on p57 results: p57-negative cases diagnosed as complete hydatidiform moles without genotyping; all p57-positive cases genotyped. Of the 678 cases, 645 were definitively classified as complete hydatidiform mole (201), partial hydatidiform mole (158), non-molar (272), and androgenetic/biparental mosaic (14); 33 were unsatisfactory, complex, or problematic. Of the 201 complete hydatidiform moles, 104 were p57-negative androgenetic and an additional 95 were p57-negative (no genotyping), 1 was p57-positive (retained maternal chromosome 11) androgenetic, and 1 was p57-non-reactive androgenetic; 90 (85%) of the 106 genotyped complete hydatidiform moles were monospermic and 16 were dispermic. Of the 158 partial hydatidiform moles, 155 were diandric triploid, with 154 p57-positive, 1 p57-negative (loss of maternal chromosome 11), and 1 p57-non-reactive; 3 were triandric tetraploid, with 2 p57-positive and 1 p57-negative (loss of maternal chromosome 11). Of 155 diandric triploid partial hydatidiform moles, 153 (99%) were dispermic and 2 were monospermic. Of the 272 non-molar specimens, 259 were p57-positive biparental diploid, 5 were p57-positive digynic triploid, 2 were p57-negative biparental diploid (no morphological features of biparental hydatidiform mole), and 6 were p57-non-reactive biparental diploid. Of the 14 androgenetic/biparental mosaics with discordant p57 expression, 6 were uniformly mosaic and 8 had a p57-negative androgenetic molar component. p57 expression is highly correlated with genotyping, serves as a reliable marker for diagnosis of complete hydatidiform moles, and identifies androgenetic cell lines in mosaic conceptions. Cases with aberrant and discordant p57 expression can be correctly classified by genotyping.

Diagnostic reproducibility of hydatidiform moles: ancillary techniques (p57 immunohistochemistry and molecular genotyping) improve morphologic diagnosis for both recently trained and experienced gynecologic pathologists

Distinction of hydatidiform moles from nonmolar specimens (NMs) and subclassification of hydatidiform moles as complete hydatidiform mole (CHM) and partial hydatidiform mole (PHM) are important for clinical practice and investigational studies; however, diagnosis based solely on morphology is affected by interobserver variability. Molecular genotyping can distinguish these entities by discerning androgenetic diploidy, diandric triploidy, and biparental diploidy to diagnose CHMs, PHMs, and NMs, respectively. Eighty genotyped cases (27 CHMs, 27 PHMs, 26 NMs) were selected from a series of 200 potentially molar specimens previously diagnosed using p57 immunohistochemistry and genotyping. Cases were classified by 6 pathologists (3 faculty level gynecologic pathologists and 3 fellows) on the basis of morphology, masked to p57 immunostaining and genotyping results, into 1 of 3 categories (CHM, PHM, or NM) during 2 diagnostic rounds; a third round incorporating p57 immunostaining results was also conducted. Consensus diagnoses (those rendered by 2 of 3 pathologists in each group) were also determined. Performance of experienced gynecologic pathologists versus fellow pathologists was compared, using genotyping results as the gold standard. Correct classification of CHMs ranged from 59% to 100%; there were no statistically significant differences in performance of faculty versus fellows in any round (P-values of 0.13, 0.67, and 0.54 for rounds 1 to 3, respectively). Correct classification of PHMs ranged from 26% to 93%, with statistically significantly better performance of faculty versus fellows in each round (P-values of 0.04, <0.01, and <0.01 for rounds 1 to 3, respectively). Correct classification of NMs ranged from 31% to 92%, with statistically significantly better performance of faculty only in round 2 (P-values of 1.0, <0.01, and 0.61 for rounds 1 to 3, respectively). Correct classification of all cases combined ranged from 51% to 75% by morphology and 70% to 80% with p57, with statistically significantly better performance of faculty only in round 2 (P-values of 0.69, <0.01, and 0.15 for rounds 1 to 3, respectively). p57 immunostaining significantly improved recognition of CHMs (P<0.01) and had high reproducibility (κ=0.93 to 0.96) but had no impact on distinction of PHMs and NMs. Genotyping provides a definitive diagnosis for the ∼25% to 50% of cases that are misclassified by morphology, especially those that are also unresolved by p57 immunostaining.

Diagnostic reproducibility of hydatidiform moles: ancillary techniques (p57 immunohistochemistry and molecular genotyping) improve morphologic diagnosis

Distinction of hydatidiform moles (HMs) from nonmolar specimens (NMs) and subclassification of HMs as complete hydatidiform moles (CHMs) and partial hydatidiform moles (PHMs) are important for clinical practice and investigational studies; yet, diagnosis based solely on morphology is affected by interobserver variability. Molecular genotyping can distinguish these entities by discerning androgenetic diploidy, diandric triploidy, and biparental diploidy to diagnose CHMs, PHMs, and NMs, respectively. Eighty genotyped cases (27 CHMs, 27 PHMs, and 26 NMs) were selected from a series of 200 potentially molar specimens previously diagnosed using p57 immunostaining and genotyping. Cases were classified by 3 gynecologic pathologists on the basis of H&E slides (masked to p57 immunostaining and genotyping results) into 1 of 3 categories (CHM, PHM, or NM) during 2 diagnostic rounds; a third round incorporating p57 immunostaining results was also conducted. Consensus diagnoses (those rendered by 2 of 3 pathologists) were determined. Genotyping results were used as the gold standard for assessing diagnostic performance. Sensitivity of a diagnosis of CHM ranged from 59% to 100% for individual pathologists and from 70% to 81% by consensus; specificity ranged from 91% to 96% for individuals and from 94% to 98% by consensus. Sensitivity of a diagnosis of PHM ranged from 56% to 93% for individual pathologists and from 70% to 78% by consensus; specificity ranged from 58% to 92% for individuals and from 74% to 85% by consensus. The percentage of correct classification of all cases by morphology ranged from 55% to 75% for individual pathologists and from 70% to 75% by consensus. The κ values for interobserver agreement ranged from 0.59 to 0.73 (moderate to good) for a diagnosis of CHM, from 0.15 to 0.43 (poor to moderate) for PHM, and from 0.13 to 0.42 (poor to moderate) for NM. The κ values for intraobserver agreement ranged from 0.44 to 0.67 (moderate to good). Addition of the p57 immunostain improved sensitivity of a diagnosis of CHM to a range of 93% to 96% for individual pathologists and 96% by consensus; specificity was improved from a range of 96% to 98% for individual pathologists and 96% by consensus; there was no substantial impact on diagnosis of PHMs and NMs. Interobserver agreement for interpretation of the p57 immunostain was 0.96 (almost perfect). Even with morphologic assessment by gynecologic pathologists and p57 immunohistochemistry, 20% to 30% of cases will be misclassified, and, in particular, distinction of PHMs and NMs will remain problematic.

Comparison of fluorescence in situ hybridization, p57 immunostaining, flow cytometry, and digital image analysis for diagnosing molar and nonmolar products of conception

Pathologic examination of products of conception (POC) is used to differentiate hydropic abortus (HA), partial hydatidiform mole (PM), and complete hydatidiform mole (CM). Histologic classification of POC specimens can be difficult, and ancillary testing is often required for a definitive diagnosis. This study evaluated 66 POC specimens by flow cytometry, digital image analysis, p57 immunohistochemical analysis, and fluorescence in situ hybridization (FISH). The final diagnosis, based on the combined analysis of all test results, included 33 HAs, 24 PMs, and 9 CMs. The p57 immunostain identified 9 CMs that were evaluated as nontriploid by all other techniques. FISH seems to have the best accuracy (100%) for determining whether a specimen contains a triploid chromosome complement. These data suggest that the combination of p57 and FISH seems to be the best ancillary testing strategy to aid pathologists in the appropriate identification of CM, PM, and HA in POC specimens.

Immunohistochemical expression of p57 in placental vascular proliferative disorders of preterm and term placentas

P57 protein is implicated in some human imprinting disorders such as hydatiform mole and Beckwith-Wiedemann syndrome (BWS), both characterized by mesenchymal and vascular placental abnormalities. We investigated p57 immunohistochemical expression in placental vascular proliferative disorders of preterm and term placentas, including chorangiosis (n = 5), chorangiomatosis (n = 2), chorangiomas (n = 7), umbilical cord angioma (n = 1), and placental mesenchymal dysplasia (PMD) (n = 7). P57 was expressed in decidua, cytotrophoblast, intermediate trophoblast and stromal cells of normal terminal, intermediate and stem villi, umbilical cord, chorangiosis, chorangiomatosis, and chorangiomas. In contrast, there was a loss of p57 expression in stromal cells of dysplastic stem villi in all cases of PMD regardless of whether associated with BWS or not. P57 seems to be involved in the pathogenesis of a subset of placental vascular proliferative disorders in preterm and term placentas, such as PMD. The loss of p57 expression in PMD could be of diagnostic value in helping to distinguish this rare placental lesion from its mimickers.

Genotypic analysis of hydatidiform mole: an accurate and practical method of diagnosis

Molar gestations are defined at the genetic level by their unique parental chromosomal compositions. Their diagnosis, however, currently relies largely on histologic features and on the occasional support of ancillary immunohistochemical and DNA ploidy analyses. We sought to validate DNA genotyping for the routine diagnosis and subtyping of hydatidiform moles (HMs) by analyzing 52 cases of molar pregnancy and their morphologic mimics. DNA was extracted from microdissected chorionic villi and paired maternal endometrial tissue from unstained paraffin sections and analyzed by AmpFlSTR Identifiler PCR Amplification system (Applied Biosystems, Inc). DNA genotyping was informative in all cases with input template DNA amounts ranging from 1.5 to 2.5 ng. Among 38 cases of HMs confirmed by DNA genotyping, there were 26 complete moles with diandric paternal-only genomes (24 homozygous and 2 heterozygous) and 12 partial moles with diandric, monogynic genomes (11 heterozygous and 1 homozygous). All nonmolar cases, including 10 cases of mimics of HM, demonstrated a balanced, biallelic profile of both maternal and paternal origin. Our study demonstrates the applicability of DNA genotyping, the molecular approach for the diagnosis, and subtyping of molar pregnancy, to the daily clinical practice.