Myomatous erythrocytosis syndrome with unusually normal serum erythropoietin levels.

Myoma uteri is the most common benign tumour in women, but myomatous erythrocytosis syndrome (MES) is rare. MES is characterised by erythrocytosis, a myomatous uterus and blood normalization after hysterectomy or myomectomy. It increases the risk of thromboembolic events, making early recognition crucial.A premenopausal, nulliparous woman in her 50s with dyslipidaemia and obesity presented with a 20-week-sized abdominopelvic mass but no abnormal uterine bleeding. CT imaging revealed a large right adnexal mass. Lab tests showed isolated erythrocytosis with normal tumour markers and serum erythropoietin (Epo). Hysterectomy and bilateral salpingo-oophorectomy confirmed multiple uterine myomas, the largest measuring 19.5 cm, along with a right ovarian haemorrhagic cyst. Postoperatively, her blood levels normalised, confirming MES.The exact mechanism remains unclear but may involve Epo production. While Epo is often linked to myomas, some cases, like ours, show normal levels, highlighting the need for further research to understand MES and develop targeted treatments.