Clear cell endometrial carcinoma precursors: presentation of two cases and diagnostic issues

Background The precursors of clear cell endometrial carcinoma (CC-EC) are still undefined. Here, we deal with the diagnostic issues related to CC-EC precursors by presenting a morphological, immunophenotypical and molecular study of two representative cases and discussing the relevant literature. Case presentation Our and previous cases suggest that clear cell endometrial intraepithelial carcinoma (CC-EIC) is a real entity, which may be distinguished from metaplastic/reactive changes and from its serous counterpart. CC-EIC appears associated with atrophic polyps and may be diagnosed based on morphological and immunophenotypical features of CC-EC in the absence of invasive disease. We described a p53-mutant putative precursor characterized by high-grade nuclei in the absence of other distinctive features. Two putative low-grade precursors resembled atypical tubal metaplasia and endometrial intraepithelial neoplasia, although immunohistochemistry could not support their relationship with CC-EC. Conclusions In conclusion, pathologists should be aware of the existence of CC-EIC, since its correct diagnosis may be crucial for a correct patient management. Although several putative earlier precursors have been described, they does not show univocal features that allow their recognition in the common practice. Further studies are necessary in this field.

Automated summary

The precursors of CC-EC, including CC-EIC, can be diagnosed based on morphological and immunophenotypical features, distinguishing them from metaplastic/reactive changes and their serous counterpart. Despite various putative earlier precursors, there is no clear-cut features for their recognition in common practice, calling for further studies in this field.