ABSTRACT
OBJECTIVE: To determine the accuracy of intraoperative frozen section diagnosis of ovarian tumors according to malignancy status. MATERIAL AND METHOD: From May, 1999 to October, 2004 at Songklanagarind Hospital, a total of 229 ovarian specimens were transferred from the operating room to the Department of Pathology for intraoperative frozen section. All cases of deferred diagnosis and disagreement between frozen and permanent paraffin section were reviewed. RESULTS: Intraoperative frozen section diagnosis of all 229 ovarian specimens revealed 54.1% benign tumors, 8.3% borderline tumors, 30.6% malignant tumors, and 7% deferred diagnoses. The final paraffin section diagnoses revealed 52.4% benign tumors, 9.2% borderline tumors, and 38.4% malignant tumors. Mean tumor diameter of the agreement cases were 12.58 +/- 5.39 cm, disagreement cases were 17.64 +/- 6.83 cm, and deferred cases were 19.33 +/- 6.50 cm. The mean diameter of mucinous tumors was significantly different comparing between disagreement cases to agreement cases and deferred cases to agreement cases. The overall accuracy was 89.7%. Sensitivity was highest in the benign group at 98.2% and lowest in the borderline group at 57.1%. The sensitivity and specificity for benign, borderline, and malignant tumors were 98.2%, 57.1%, 86.1%, and 87.0%, 96.4%, 98.5%, respectively. The Positive Predictive Value (PPV) and Negative Predictive Value (NPV) for benign, borderline, malignant tumors were 89.5%, 63.2%, 97.1% and 97.8%, 95.4%, 92.3%, respectively. CONCLUSION: Intraoperative frozen section diagnosis appears to be an accurate technique for the histopathologic diagnosis of ovarian tumors. However, limitations in use of frozen section must be recognized such as large specimens, especially mucinous subtype. Regular re-evaluation or consultation concerning disagreements between frozen section diagnosis and final permanent paraffin diagnosis should be conducted by both surgeons and pathologists as part of quality assurance to determine the most appropriate intraoperative management for patients with ovarian tumors.