[Trophoblastic gestational diseases. Triploid syndrome, perivillous trophoblastic hyperplasia, trophoblastic pseudotumor, trophoblastic microcarcinoma and carcinoma].

Comparing the cytogenetic and morphological data on cases of hyperplasia and neoplasia of the trophoblast allows some conditions to be better defined and separated. The term partial mole or embryonic mole should be replaced by the term triploid syndrome because of the especially strong correlation between the triploid caryotype and the special aspect of the placenta. Triploidy is usually the result of fecundation of a haploid ovule by two spermatozoids, probably due to the similarity of the haploids of the two parents, as is suggested by the study of HLA antigens. Classical hydatidiform mole, or perivillous trophoblastic hyperplasia, is usually discovered earlier, during an ultrasound examination or abortion and its histological diagnosis is easy. The caryotype of complete hydatidiform mole is diploid, nearly always XX, with the two sex chromosomes coming from the father (the maternal sex chromosome being eliminated). The caryotype of vesicular dystrophia without trophoblastic hyperplasia is, on the other hand, normal. Trophoblastic microcarcinomas have a better known presentation. And trophoblastic carcinomas are distinct from non-trophoblastic neoplasms which secrete HCG and from benign trophoblastic pseudo-tumors which are often non-secretory.