Discrepancies in the histological diagnosis of hydatidiform mole.

Sections of tissue from 256 patients on which a histological diagnosis of hydatidiform mole had been made were reviewed by a visiting pathologist. There was agreement between the reporting pathologists and the visiting pathologist in only 55.1 per cent of cases, a less severe diagnosis was made by the visiting pathologist in 42.2 per cent of cases. The disagreement was as high as 66.6 per cent with pathologists who rarely worked in the gynaecological field. This study casts serious doubt on the consistency of the histological diagnosis of hydatidiform mole made in any one laboratory and between different laboratories. It is suggested that in epidemiological studies the diagnosis should be made by a panel of pathologists using strict histological criteria and in an individual laboratory diagnosis should be made or confirmed by a pathologist experienced in gynaecological pathology.