Division of Gynecologic Pathology

Hydatidiform Mole Evaluation

We perform diagnostic consultations and ancillary testing for evaluation of potentially molar products of conception specimens.

We evaluate the glass slides and request one or more paraffin blocks (if not already provided with the slides) for ancillary testing. We require blocks that contain well-separated areas of villous and decidual tissue (the latter must be pure and free of any implantation site elements [fibrinoid material with intermediate trophoblastic cells]). We cut H&E slides and unstained sections according to a specific protocol. This protocol generates a 4-micron unstained slide for p57 immunohistochemical analysis and a series of 10-micron unstained slides (cut with PCR precautions) with flanking H&E slides for guiding microdissection. Given the specifics of this protocol, we require paraffin blocks and cannot use routinely cut unstained slides from the originating laboratory. Once the block is cut in our Immunopathology Laboratory, p57 immunohistochemical analysis is used to triage cases for genotyping. For cases with appropriate morphology, diagnosis of complete hydatidiform mole is rendered when p57 is negative and satisfactory. These cases are not routinely genotyped but can be if requested by the contributing laboratory. All p57-positive cases are subjected to genotyping in our Molecular Diagnostics Laboratory. Testing is performed generally twice a week. Given this schedule of testing, results are generally available by 5 working days from the time of accessioning into the molecular laboratory, unless technical factors necessitate repetition of the analysis.