The diagnosis of molar pregnancy by sonography and gross morphology

Background. In modern times molar pregnancies are often terminated before classical symptoms have developed. Sonography may not be conclusive and gross macroscopy may not reveal vesicles. If the aborted material is not sent for microscopy adequate follow-up of these patients will not be performed. The objective of this study was to evaluate the percentage of molar cases that potentially will be missed in a setting where material is submitted for histopathology only when sonography and/or gross macroscopy suggest complete- or partial hydatidiform mole. Methods. Charts from 135 patients with complete hydatidiform mole (75) and partial hydatidiform mole (60) between 1989-1997 were evaluated. Results. In complete hydatidiform mole sonography had been performed in 68 patients. The correct diagnosis had been suspected in 84% of the cases with the aid of sonography and/or gross macroscopy. In partial hydatidiform mole the correct diagnosis was suspected in only 30% of the cases. Three patients with complete mole developed persistent disease despite negative sonography and/or gross macroscopy. One patient with partial mole that was only documented by microscopy also developed sequelae. Conclusion. In a setting where material from curettages in early pathological pregnancies are not routinely sent for histopathology 16% and 70% of complete- and partial hydatidiform moles respectively will be missed. Since a subset of these 'discrete' moles will eventually require chemotherapy, this policy could have serious consequences.