Aims: Recent studies have shown that CD10 is a useful immunohistochemical marker of normal endometrial stroma and of endometrial stromal neoplasms. The aim of this study was to investigate whether CD10 immunoreactivity is present in ectopic endometrial stroma and whether staining is of value in confirming a diagnosis of endometriosis.
Methods/results: Twenty five cases of endometriosis were stained with a commercially available antibody against CD10. Endometrial stromal cells were positive in 22 of 25 cases. There was little or no staining of other tissues.
Conclusions: CD10 immunoreactivity is largely maintained in endometrial stromal cells located outside the uterus. Immunohistochemical staining with CD10 may be of value in confirming a diagnosis of endometriosis when there is morphological doubt.