Pathologic evaluation of uterine leiomyoma treated with radiofrequency ablation

To explore the mechanism by which radiofrequency ablation (RFA) treats uterine leiomyoma by observing the features of the lesions caused by RFA to leiomyoma tissue.

Specimens from treated lesions were observed after hysterectomy was performed immediately (acute test) or on the third day (chronic test) following treatment in 2 groups of 30 patients. Histopathologic studies were also performed for all specimens, with untreated specimens as controls.

For the acute and chronic tests, specimens from the RFA-treated lesions included the center segment (group 1); the marginal segment (group 2); the segment 1-cm away from the margin (group 3); and the segment 2-cm away from the margin (group 4). In the acute test, group 1 showed a sharply demarcated area of coagulative necrosis that did not express estrogen receptor (ER) or progesterone receptor (PR); group 2 showed a severe hydropic degeneration or necrosis; and group 3 showed regular leiomyoma cells. The expression of ER and PR was significantly less in groups 2 and 3 than in the control group (P<0.05), but ER and PR expression in group 4, which had normal leiomyoma cells, was the same as in the control group (P>0.05). In the chronic test, group 1 showed carbonization and coagulation necrosis without ER or PR expression. There was severe hemorrhage and thrombosis in group 2; hyaline degeneration and tissue granulation in group 3; and mild degeneration in group 4. The expression of ER and PR was significantly lower in groups 2, 3, and 4 than in the control group (P<0.05).

Radiofrequency ablation might treat uterine leiomyomas by inducing coagulative necrosis and depressing ER and PR expression.