Histologic findings in hysterectomies after endometrial ablation

Endometrial ablation for abnormal uterine bleeding is used as a less invasive alternative to hysterectomy, however, in cases of treatment failure hysterectomy may be finally performed. The histologic changes in these post-treatment uteri are not well-described.

To describe the histological findings in post-endometrial ablation uteri.

During a ten-year period, 321 patients were treated with endometrial ablation. Twenty-five patients (7.8%), 10 treated with NovaSure® and 15 treated with ThermaChoice® endometrial ablation were finally subjected to hysterectomy mostly due to persistent uterine bleeding. Histologic features of these hysterectomies are described.

The patients' age ranged from 33 to 73 years (mean 44.5) and 34-53 (mean 42) for the NovaSure® and ThermaChoice® group, respectively. The time from endometrial ablation to hysterectomy was 2-24 months (mean 8.8) and 2-60 months (mean 23.2) for the two groups, respectively (p = 0.01). Hysterectomies performed later (mean 22 months) showed no fibrosis (p = 0.04) compared with those performed earlier (mean 5 months). Endometrial lining was found more frequently in hysterectomies performed later (mean 13 months) than those performed earlier (mean 2 months, p = 0.0004). Abundant necrotic tissue of myometrial origin was found in 28% of the cases, but it was not associated with the time of hysterectomy (p = 0.2). A zonation effect and vascular changes also seen. Granulomatous reaction was not found. Ten patients (40%) harbored adenomyosis and another three (12%) extensive leiomyomas/diffuse leiomyomatosis.

Necrosis, fibrosis and vascular changes are found during the first year of post-thermal uterine effect. Hysterectomies performed later show less prominent changes and almost normal endometrial lining. Adenomyosis is found in an important part of post-endometrial ablation hysterectomies.