Do nontriploid partial hydatidiform moles exist? A histologic and flow cytometric reevaluation of nontriploid specimens.

Objective: To study whether nontriploid partial hydatidiform moles truly exist.

Study Design: We conducted a reevaluation of pathology and ploidy in 19 putative nontriploid partial hydatidiform moles using standardized histologic diagnostic criteria and repeat flow cytometric testing by the Hedley technique.

Results: On review of the 19 moles, 53% (10/19) were diploid nonpartial moles (initially pathologically misclassified), and 37% (7/19) were triploid partial moles (initial ploidy misclassifications).