Malignant transformation of residual endometriosis after hysterectomy: a case series.

Objective: To explore the role of long-standing hormone replacement therapy (HRT) in the malignant transformation of endometriosis.

Design: Short case series. Three cases of women with pelvic clearance receiving long-standing HRT studied in detail.

Setting: Teaching hospital in the United Kingdom (Gynaecological Cancer Centre) (Institutional Review Board approval was not obtained as it was not deemed necessary, this being a case series).

Patient(s): Women with a history of pelvic clearance for endometriosis and longstanding HRT.

Intervention(s): HRT.

Main Outcome Measure(s): Malignant transformation of endometriosis.

Result(s): Long-standing HRT in all three women with pelvic clearance for endometriosis resulted in malignant transformation of residual endometriosis many years after the initial surgery. All cases presented with a new pelvic lesion.

Conclusion(s): The diagnosis of malignant transformation needs to be considered in women with a history of endometriosis and with long-term HRT use in whom a new pelvic lesion is detected. The risk of malignant transformation in women with endometriosis after pelvic clearance receiving HRT needs to be explored further. Surveillance with CA-125 and imaging in such cases to predict recurrence or malignant transformation needs to be studied further in a research setting.