Residual trophoblastic disease in association with partial hydatidiform mole.

A 10-year retrospective study was carried out of cases diagnosed as hydatidiform mole at the University of Hong Kong. Strict morphologic criteria established in a previous report were used to study the association of the partial mole syndrome with residual trophoblastic disease. Of the total of 138 cases available, 13 were found to be partial moles, 1 of which was followed by trophoblastic disease that required chemotherapy. This subsequently proved to be an invasive (partial) mole, the first example of its kind to be verified by pathology. The extent of the association between partial mole and subsequent trophoblastic disease and the spectrum of the pathologic lesions actually underlying the latter remain to be determined by further retrospective and prospective studies.