Characteristic sonographic vesicular pattern of a complete hydatidiform mole in the early first trimester

To evaluate the sonographic vesicular pattern of a complete hydatidiform mole (CHM) in the early first trimester.

A retrospective study was performed on 30 cases of histologically proven CHMs in the early first trimester. Two radiologists reviewed the sonograms of all cases before evacuation and determined the extent of vesicular pattern for each case independently. The extent of vesicular area was divided into 4 categories: absent, mild (less than one third), moderate (one third to two thirds) or severe (more than two thirds). Interobserver agreement between the reviewers was calculated by weighted kappa.

The mean gestational age of all cases at ultrasound was 7.6 +/- 2.0 weeks (mean +/- SD) with a range of 5.0-12.5 weeks. Reviewer 1 classified the extent of sonographic vesicular pattern as absent (10%), mild (63.3%), moderate (20%) and severe (6.7%). Reviewer 2 classified the cases as absent (10%), mild (53.3%), moderate (33.3%) and severe (3.3%). There was almost perfect agreement in categorizing the vesicular pattern between the reviewers (kappa = 0.866).

A mild sonographic vesicular pattern of CHM was common in the early first trimester.