A giant uterine myometrium cyst mimicking an ovarian cyst in pregnancy: An uncommon presentation of hydropic degeneration of uterine fibroid

Myometrial cysts of the uterus are extremely rare. Uterine leiomyomas commonly undergo degenerative changes, which can lead to variable imaging features. Diffuse hydropic change is an unusual form that presents a considerable diagnostic challenge to both radiologists and pathologists. A 27-year old nulliparous patient admitted to our hospital for antenatal care and left sided pelvic pain. Transvaginal ultrasonographic examination revealed a 20 cm intramural cystic lesion in the left region of the corpus uteri suspicious of degenerated myoma. Repeated aspiration was done. Spontaneous abortion occurred in the first trimester. Rapid distension of the abdomen despite repeated aspirations occurred. MRI revealed degenerated myoma. Ultrasound performed one day before surgery revealed a turbid content instead of the clear fluid. Laparotomy was performed revealing a huge interstitial myoma with bloody collection inside so, myomectomy was performed. Histopathology showed hydropic degenerated myoma. Although fibroids usually have a characteristic sonographic appearance, degenerating myomas have variable patterns and can pose a diagnostic dilemma. Extensive cystic degeneration can mimic an ovarian tumour.