Re-evaluation of hydatidiform mole by DNA fingerprint method: the discrepancy in the diagnoses by pathological finding and the DNA fingerprint method

Immunohistochemical Characterization of p57Kip2 Expression in Tetraploid Hydropic Placentas

Context.—Because there are differences in the origin, morphology, and natural history of hydropic placental villous issues, it is important to identify and document rare specimens that deviate from the diploid complete hydatidiform mole (CM), triploid partial hydatidiform mole (PM), or diploid hydropic abortion (HA). Tetraploid hydropic placentas have rarely been studied.

Objectives.—To evaluate the frequency of p57Kip2 protein (p57) expression in tetraploid hydropic placentas and to determine its clinicopathologic significance.

Design.—Forty hydropic DNA tetraploid placental specimens were evaluated by immunohistochemistry of formalin-fixed tissues, using a monoclonal antibody against p57, a putative paternally imprinted inhibitor gene. DNA ploidy in all cases was analyzed by flow cytometry.

Results.—Thirty cases were histologically diagnosed as CMs, 10 were HAs, and none were PMs. In all HAs, nuclear p57 was strongly expressed in cytotrophoblasts, intermediate trophoblasts, and villous stromal cells. In contrast, in CMs, p57 expression in cytotrophoblasts and villous stromal cells was either absent (26 cases) or very low (4 cases). Assuming that the degree of molar change roughly correlates with the proportion of paternal chromosomes present, all chromosomes might be paternally derived in all tetraploid CMs and the 10 HAs, including 2 that were karyotyped as 92,XXYY or 90,XXYY,−13,−14, which were presumably due to 2 sets of chromosomes each from paternal and maternal origin.

Conclusions.—Expression of p57 is aberrant in tetraploid CMs. This finding is in line with the hypothesis that the loss of p57 is involved in the abnormal development of androgenetic CMs. For the evaluation of a patient with trophoblastic disease, p57 immunostaining is an ancillary diagnostic method that may be used in concert with flow cytometry.

Flow cytometric and clinicopathologic study of complete hydatidiform moles with special reference to the significance of cytometric aneuploidy

OBJECTIVE

As complete hydatidiform moles (CMs) have been studied less with respect to aneuploidy and its clinical implications, the significance of cytometric aneuploidy in CMs was evaluated.

METHODS

Two hundred thirty-nine CMs were studied clinicopathologically and analyzed by flow cytometry using formalin-fixed paraffin-embedded tissues.

RESULTS

Of 239 CMs, 182 were diploid, 30 were tetraploid, and 27 were aneuploid (nontriploid/tetraploid aneuploid). There were no significant histologic differences among the diploid, tetraploid, and aneuploid CMs. Persistent disease developed in 20 of 114 CMs (17.6%) (16 of 77 diploid, 4 of 18 tetraploid, and none of 19 aneuploid CMs). Eight diploid and three tetraploid CMs were invasive, and one patient each with diploid CM and tetraploid CM developed choriocarcinoma and none of 19 patients with aneuploid CMs had sequelae.

CONCLUSION

These results suggest that aneuploid CMs are associated with less risk for persistent disease than diploid or tetraploid CMs. DNA ploidy status may be an independent predictor of persistent disease.

Genetic differentiation of complete hydatidiform moles coexisting with normal fetuses by short tandem repeat-derived deoxyribonucleic acid polymorphism analysis

OBJECTIVE

We applied deoxyribonucleic acid polymorphism analysis on the basis of differences in the number of short tandem repeat sequences to genetically differentiate dizygotic twins with complete hydatidiform moles and normal fetuses from partial moles presenting a similar appearance.

STUDY DESIGN

Six pregnant women exhibiting apparent moles and coexisting fetuses were the subjects of this study. Eight polymorphic loci including short tandem repeat sequences were amplified by polymerase chain reaction from deoxyribonucleic acid of peripheral leukocytes of parents, umbilical cord, grossly normal placenta-villi, and molar tissue. The segregation of alleles among samples were determined by comparing band patterns on polyacrylamide gels.

RESULTS

In all 6 cases amplifications of polymorphic loci provided sufficient information to determine the parental origin. At informative loci the alleles of cord and placenta-villi were transmitted from both patients and husbands whereas molar tissue had only paternal alleles. These allele segregations indicated 2 different genetic origins, namely, normal parental for a fetus and androgenetic for molar tissue, and thus the diagnosis of dizygotic twins with a complete hydatidiform mole and a normal fetus was made. Additionally, the molar component was defined as a heterozygous mole in 2 cases.

CONCLUSION

Short tandem repeat-derived deoxyribonucleic acid polymorphism analysis was demonstrated to be a useful and precise procedure for the differential diagnosis of a complete hydatidiform coexisting with a normal fetus and the determination of its zygosity as well.

Genetic analysis of hydatidiform moles in paraffin wax embedded tissue using rapid, sequence specific PCR-based HLA class II typing

AIMS

To determine the applicability of rapid, sequence specific polymerase chain reaction (PCR)-based HLA class II genotyping for the distinction of complete from partial hydatidiform moles (HM) using DNA extracted from formalin fixed and paraffin wax embedded tissue.

METHODS

Nine HM were studied. DNA was extracted from formalin fixed and paraffin wax embedded tissue after mechanical separation of decidual and molar components. HLA class II DRB (DRB1, -3, -4, and -5) and DQB1 genotyping was performed using a parallel series of PCR reactions, each of which contained sequence specific primers designed to amplify different HLA DRB and DQB1 alleles or allele groups (PCR-SSP analysis). In each case the HLA DRB and DQB1 genotypes identified within the decidua and HM were compared.

RESULTS

Within the decidual tissue, HLA DRB genotypes were assignable in all nine cases, and HLA DQB1 genotypes were identified in seven cases. Within the molar tissue, HLA DRB genotypes were assignable in seven cases, and at least one HLA DQB1 allele was identified in seven cases. Interpretation based on HLA class II genotyping was therefore possible in two cases classified on histological appearances as complete HM, in four classified as partial HM, and in one HM of uncertain type. Different HLA DRB and DQB1 haplotypes were identified within the decidual and molar tissue from both complete HM, consistent with a solely paternal origin and supporting the histological diagnosis. HLA DRB and DQB1 alleles common to the decidual and molar tissue were present within the four partial HM and the HM of histologically uncertain type, consistent with combined maternal and paternal genetic input to these HM, supporting the histological diagnosis in four cases and suggesting that the histologically equivocal case was also a partial HM.

CONCLUSION

PCR-SSP HLA class II DRB and DQB1 typing is reliably applicable to DNA extracted from formalin fixed and paraffin wax embedded tissue. Therefore, in a suitably equipped HLA typing laboratory, this technique provides a useful adjunct to histological examination for differentiation of complete from partial HM.

Twin pregnancy with a fetus and a complete hydatidiform mole

Twin pregnancy with a normal fetus and gestational trophoblastic neoplasia as a co-twin is a rare entity. We are reporting such a case and discuss its management.

Flow cytometric and clinicopathologic study of 197 hydatidiform moles with special reference to the significance of cytometric aneuploidy and literature review

In order to evaluate the significance of cytometric aneuploidy in molar placentas, we analyzed 197 hydatidiform moles by flow cytometry using formalin-fixed, paraffin-embedded tissues. Of 150 complete moles (CMs), 110 were diploid, 26 were tetraploid, and 14 were aneuploid (non-triploid/tetraploid aneuploid). Of 47 partial moles (PMs), 44 were triploid and 3 were diploid. We could not find any histologic differences among the diploid, tetraploid, and aneuploid CMs. We found that flow cytometric DNA analysis was very helpful to differentiate CM from PM. Persistent diseases developed in 12 of 69 CMs (17.4%) (9 of 47 diploid and 3 of 14 tetraploid CMs) and in none of 26 PMs (0%). Four diploid and 2 tetraploid CMs were invasive and one each with diploid and tetraploid CM developed choriocarcinoma and none of 8 aneuploid CMs had sequelae; however, there was no correlation between DNA ploidy and clinical outcome in the CMs. These results suggest that cytometric aneuploidy (non-diploidy) in CMs is not an independent predictor of persistent disease.

Complete hydatidiform mole in twin pregnancy: differentiation from partial mole with interphase cytogenetic and DNA cytometric analyses on paraffin embedded tissues

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.

In situ choriocarcinoma arising in partial hydatidiform mole: implications for the risk of persistent trophoblastic disease

The risk of persistent trophoblastic disease following partial hydatidiform mole is controversial. In spite of claims that 4 to 11% of cases require chemotherapy, there is a paucity of affected patients in the literature. A critical review of those patients suggests an alternative or unproven diagnosis in the majority. An instance of placental in situ choriocarcinoma arising in a partial mole is reported. Because in situ choriocarcinoma may represent the incipient lesion in the majority of the one-third of cases of gestational choriocarcinoma that follow a normal pregnancy, we postulate that the presence of the in situ lesion in a partial mole supports the view that the risk of persistent trophoblastic disease may be no greater after partial mole than after a normal gestation.