Ultrasound-guided fine needle aspiration of ovarian masses: Assessment of diagnostic accuracy and risk stratification using a categorical reporting system.

ABSTRACT

INTRODUCTION: The present study was undertaken to assess the accuracy of fine needle aspiration cytology (FNAC) and cell-block immunocytochemistry, and to estimate the risk of malignancy, using a categorical reporting system, in the diagnosis of ovarian masses. METHODS: This was a 5-year retrospective study of FNAs of ovarian masses. The cytological diagnoses were categorised as inadequate, non-neoplastic, benign neoplasms, indeterminate for malignancy, suspicious for malignancy and malignant neoplasms. The cytology was correlated with the corresponding histopathology to assess the diagnostic accuracy and risk of malignancy associated with each diagnostic category. RESULTS: Of a total of 66 703 FNAs performed during the study period, 580 (0.9%) were performed on ovarian masses. Of these, 40 (6.9%) were reported as non-neoplastic; 76 (13.1%) as benign neoplasms; 14 (2.4%) as indeterminate for malignancy, 48 (8.3%) as suspicious for malignancy, 337 (58.1%) as malignant neoplasms and 65 (11.2%) as inadequate for interpretation. Immunocytochemistry (ICC) was performed on 99 (17%) aspirates. Subsequent histopathology was available in 208 (35.8%) cases. On cyto-histopathological correlation, 183 (88%) were concordant and 25 (12%) were discordant. The overall sensitivity, specificity, positive and negative predictive values and diagnostic accuracy for diagnosing ovarian malignancy were 88.4%, 85.7%, 96.8%, 60.0% and 88% respectively. Risk of malignancy for each category was 80%, 0%, 4.5%, 66.7%, 88.5% and 98.5% respectively. CONCLUSIONS: Ultrasound-guided FNAC has high specificity and diagnostic accuracy for preoperative diagnosis of ovarian malignancies and hence is a valid diagnostic procedure in certain clinical situations. Reporting using a categorical system imparts uniformity and also provides the clinicians with an associated risk of malignancy to guide further management.