Villous cytotrophoblast proliferating potential in complete and partial hydatidiform mole: diagnostic value of silver-stained nucleolar organizer region (AgNOR)-associated proteins.

Aside from their typical morphologic features, complete (CHM) and partial hydatidiform mole (PHM) are characterized by variable trophoblastic proliferation and/or atypia. CHM and PHM usually present little diagnostic difficulty. However, some may be extremely difficult to distinguish by morphologic features alone. Therefore, we investigated the diagnostic value of silver-stained nucleolar organizer region (AgNOR)-associated proteins in cytotrophblasts as compared to cytogenetic features of nine CHM, nine PHM and six non-molar spontaneous embryonic abortions (controls), as well as of two suspected CHM and two histologically suspected PHM. Tissue sections were submitted to autoclave pretreatment and to silver colloid solution. The proliferating potential of cytotrophoblasts was determined by the analysis of mean number and mean area of AgNORs per nucleus using a PC-based image analysis system. Mean values of AgNOR parameters were significantly different from each other (p < 0.001). Each of the four cases of tentative diagnosis could be assigned to the corresponding group of examined trophoblastic lesions. The evaluation of AgNORs in cytotrophoblasts contributes to a reliable discrimination of CHM and PHM; this fairly simple and economical method could serve as an useful addition to conventional methods of diagnosis in gestational trophoblastic disease.