Differential diagnosis of hydatidiform moles.

The clinicopathological features of hydatidiform moles are described. Criteria are given for distinguishing between partial and complete moles and it is stressed that this distinction can be difficult when complete moles are detected, by ultrasound, at an early stage of their development: the diagnostic value of cytometry is emphasized. The distinction between partial moles and hydropic abortuses rests entirely upon morphological grounds and is somewhat subjective, being associated with a high degree of interobserver variance.