Comparison Between Pathological Diagnosis and Cytogenetic Diagnosis by Short Tandem Repeat Polymorphism Analysis of Suspected Molar Pregnancies.

Objective: To elucidate the diagnostic accuracy of macroscopic and histopathological diagnoses of molar pregnancy as compared with cytogenetic diagnosis as the gold standard.

Study Design: Patients were recruited for the molecular diagnostic study of suspected molar pregnancy at Chiba University Hospital between 2007 and 2011. Gynecologists performed macroscopic diagnoses immediately after the evacuation. Pathological diagnoses were then made by pathologists in routine bases without performing p57Kip2 immunostaining. Molecular cytogenetic diagnosis was performed via short tandem repeat (STR) polymorphism analysis. Androgenetic, biparental triploid, and biparental diploid villous tissues determined on STR polymorphism analysis were classified as complete hydatidiform mole (CHM), partial hydatidiform mole (PHM), and abortion, respectively.

Results: A total of 86 patients were enrolled. The number of CHMs, PHMs, and abortions on cytogenetic diagnoses were 64, 9, and 13, respectively. The concordance rate between macroscopic and cytogenetic diagnoses was 85% (CHM: 56, PHM: 4, and abortions: 13). The concordance rate between histopathological and cytogenetic diagnoses was 87% (CHM: 59, PHM: 5, and abortions: 10). The complete agreement rate among the 3 categories was 78% (CHM: 55, PHM: 3, and abortions: 10).

Conclusion: Neither macroscopic nor histopathological diagnoses were perfect, but both were quite accurate in a single trophoblastic center.