Clinicopathologic study of tetraploid hydropic villous tissues

Because there are differences in the origin, morphology, and natural history of hydropic placental villous tissues, it is important to identify and document rare specimens that deviate from the diploid complete mole (CM), triploid partial mole (PM), or diploid hydropic abortion (HA).

We clinicopathologically investigated 35 cytometric specimens of formalin-fixed, paraffin-embedded, tetraploid hydropic villous tissue.

Of 35 cases, 25 were CMs, 10 were hydropic abortions, and none were partial moles. Assuming that the degree of molar change roughly correlates with the proportion of paternal chromosomes present, all chromosomes might be paternally derived in our 25 tetraploid CMs. Ten hydropic abortions, including two that were karyotypically either 92,XXYY or 90,XXYY,-13,14, were presumably due to two sets of chromosomes each from paternal and maternal origin. Of 14 tetraploid CMs for which follow-up data were available, two developed an invasive lesion and one developed choriocarcinoma with a diploid DNA content. However, as we reported previously, tetraploidy in CMs is not considered to be an independent predictor of persistent disease.

These results indicate that patients with tetraploid CM require the same close follow-up given to diploid CM patients.