The role of pathologic evaluation of endometrial ablation resections in predicting ablation failure and adenomyosis in hysterectomy.

Endometrial ablation is commonly performed to manage heavy menstrual bleeding. However, failure in symptom control eventually requiring hysterectomy is frequent. Adenomyosis is common in such failure cases. Ablations using a resectoscope will produce an Endo-Myometrial Resection (EMR) specimen. The value of histopathologic examination of EMRs in predicting treatment failure and adenomyosis has not been addressed. We retrieved histologic material from subjects with failed ablation (persistent symptoms requiring hysterectomy) and subjects with ablation followed by clinical improvement and no hysterectomy (control group). Material was evaluated for features of an abnormal endometrial distribution suggestive of adenomyosis: myometrial fragments with endometrium on opposite edges, myometrium with endometrium in ≥3 edges and areas of endometrium completely surrounded by myometrium (endometrial islands). Hysterectomy specimens from the study group were evaluated for the presence of adenomyosis and its distribution (superficial/deep). Both study and control groups consisted of 18 patients each. The number of fragments with endometrium on opposite sides was significantly higher in the study group: 2.11 vs 0.94 in the control group (p=0.005). Conversely, maximum aggregate dimension (2.3cm vs 2.79cm), number of fragments with endometrium on three sides (4.5 vs 2.78) and number of fragments with endometrial islands (4.5 vs 4.11) did not significantly differ between groups. Adenomyosis was seen in 72.2% hysterectomies from the study group; 27.8% involved deep myometrium. None of the EMR features were statistically associated with adenomyosis. Certain endomyometrial distribution patterns in EMR specimens correlate with future ablation failure and need for definitive surgery. This may be explained by residual endometrial tissue not resected due to a markedly irregular endomyometrial interface. Adenomyosis is frequent in cases of ablation failure. However, a significant association between EMR patterns studied and adenomyosis was not observed.