Osseous metaplasia of the endometrium treated by hysteroscopic resection

A 27 year old woman presented to the infertility unit with a 6 year history of secondary infertility. She had had three previous pregnancies terminated at 8, 12 and 23 weeks, respectively, the last being in 1983, and had been taking the oral contraceptive pill until 1985. She had a normal regular menstrual cycle, with some dysmenorrhoea. The history was otherwise unremarkable. Her partner had had two children in a previous relationship. Investigation of the couple, including hormonal assessment and semen analysis, hysterosalpingography and diagnostic laparoscopy with hydrotubation, revealed no cause for the failure to conceive. They were admitted to the IVF programme. Pituitary down-regulation with buserelin was followed by superovulation with HMG, oocyte recovery and transfer of three embryos. Pregnancy was achieved during the first cycle, but the couple immediately went abroad, not returning until 13 weeks, when an ultrasound scan revealed a missed abortion. On ultrasound scans during the IVF cycle a strongly echogenic band was seen within the uterus, and this persisted after uterine evacuation (Fig. 1). Diagnostic hysteroscopy was performed and revealed a solid white plaque of tissue on the posterior wall of the uterus covering around 30% of the endometrial surface area. This was confirmed histologically to be mature woven bone with no viable cells (Fig. 2). It was decided to attempt to remove this tissue hysteroscopically using the diathermy resectoscope. This was achieved without difficulty using the 90 degree loop attachment. Histology of the plaque was reported as osseous metaplasia, and a biopsy of the underlying endometrium showed no abnormality. At the time of writing, 5 months after removal of the osseous tissue, the woman is in the first trimester of pregnancy, on this occasion having conceived spontaneously.