Comparison of endovaginal ultrasound and cytological evaluation of cystic ovarian tumors.

Endovaginal ultrasound is a good diagnostic tool for distinguishing between cystic and solid tumors. Unilocular cysts in the lower pelvis seem to carry a very low risk of malignancy in women of all ages. Cytological evaluation of the fluid from a cystic ovarian tumor has rather poor accuracy in diagnosing malignancy. For such a reason, this study compares the diagnostic accuracy of endovaginal ultrasound to that of cytology of the cyst content. Furthermore, we wanted to determine whether irrigation after puncture of a cystic tumor could increase the number of cells in the fluid and thereby increase the diagnostic accuracy of the cytological evaluation. Fifty women admitted to surgery due to a cystic tumor were endovaginally scanned the day before surgery. After the intact tumor had been removed from the abdomen, its contents were aspirated by means of a double-channelled needle. Irrigation was performed with Ringer acetate. Cytological evaluation was performed on both portions of the cyst fluid. The negative predictive value with respect to malignancy was 77% for cytology of the first portion of the aspirate, 81% for irrigation, and 100% for ultrasound. The corresponding figures for positive predictive value were 100%, 100%, and 73%. We conclude that cytological evaluation after irrigation of a cystic ovarian tumor does not significantly increase accuracy in diagnosing malignancy compared to endovaginal ultrasound.