Pre and intraoperative diagnosis of ovarian tumours: how accurate are we?
Lim FK, Yeoh CL, Chong SM, Arulkumaran S.
Department of Obstetrics and Gynaecology, National University Hospital, Singapore.
In the assessment of malignant potential of ovarian tumours, frozen section has been found to be accurate in 97.1% (168 of 173) of cases. The positive predictive value of frozen section in the diagnosis of a malignant lesion was 100% (34 of 34). Errors were mainly made in the diagnosis of borderline tumours with a predictive value of 87.5% (7 of 8). The negative predictive value was 98.4% (127 of 129). Frozen section however, was less accurate in the diagnosis of specific histological type with an accuracy rate of 91.9% (159 of 173). Macroscopic features were found to be useful in the intraoperative prediction of malignant potential. Completely cystic tumours were benign in 96.4% (108 of 167) of cases. Solid/cystic tumors were malignant in 69% (27 of 38) of cases. Completely solid tumours were malignant in 56% (9 of 16) of cases. Frozen section in completely cystic tumours only marginally improved the clinical macroscopic diagnosis of malignancy. The sensitivity and specificity of ultrasound scan in the diagnosis of malignant/borderline tumours were 82% and 86% respectively. The false negative rate of 7% makes laparoscopic excision of unsuspected malignant ovarian cyst a significant possibility. The predictive value of ultrasound scan in the diagnosis of malignant ovarian tumour was 62% (26 of 42). In the preoperative assessment of malignant potential of ovarian tumours, this study shows that ultrasound scan has a high false positive and a significant false negative rate. Careful intraoperative assessment of gross features and the use of frozen section especially in those with solid/cystic and solid tumours will help achieve a high accuracy rate in the assessment of ovarian tumours.
PMID: 9222473 [PubMed - indexed for MEDLINE]