Endometrial squamous metaplasia. An unusual response to progestin therapy of hyperplasia.

OBJECTIVE

To report the finding of squamous metaplasia within endometrial glands occurring as a result of progestin therapy of hyperplasia.

DESIGN

Case series. Retrospective analysis of two cases from 9235 accessioned endometrial biopsies.

SETTING

Hospital-based pathology laboratory processing inpatient and outpatient specimens.

PATIENTS

Two women, ages 49 and 34 years, with endometrial hyperplasia without squamous metaplasia who were treated with progestin.

RESULTS

Extensive squamous metaplasia was found in endometrial glands following progestin therapy. The post-therapy biopsies also showed progestin-related alterations but no evidence of active hyperplasia.

CONCLUSION

Squamous metaplasia in these cases appears to be a consequence of progestin therapy. The absence of hyperplasia in the progestin-treated endometrium suggests that the squamous metaplasia does not represent persistence or progression of the original hyperplastic lesion.