Evaluation of a scoring system for predicting lymph node malignancy in ultrasound guided fine needle aspiration practice

Ultrasound‐guided fine needle aspiration (USG‐FNA) has enabled cytopathologists to accurately diagnose smaller or non‐palpable lymph nodes (LN) on a regular basis. Pre‐FNA clinical and ultrasonographic factors, such as a patient's age, ratio of short to long axis diameter (S/L ratio), internal echogenicity, and the vascular pattern of a LN, are reported to be able to predict the benign or malignant nature of a LN. This study is designed to test the formula “0.06 × (age) + 4.76 × (S/L ratio) + 2.15 × (internal echo) + 1.80 × (vascular pattern)” generated from the study of Liao et al. as a scoring system for predicting LN malignancy in a cytopathologist operated USG‐FNA practice. Eighty‐three reports of USG‐FNA of LNs issued between 7/1/2008 and 4/28/2010 were reviewed. Patient's age, S/L ratio, internal echo, and vascular pattern were used to generate scores based on the aforementioned formula. A score of seven was used as a cutoff for predicting benign (<7) and malignant (>7) LNs. FNA cytology diagnosis, flow cytometric analysis as well as subsequent surgical diagnosis in some cases served as gold standard for statistical analysis. Among 46 USG‐FNA of LNs with scores > 7, 38 were malignant and eight were benign. All 37 USG‐FNA of LNs with scores < 7 were proven to be benign. The scoring system achieved 100% sensitivity, 82% specificity, 83% positive predictive value, 100% negative predictive value, and 90% accuracy. Further study of the eight “false‐positive” cases revealed that three of them (37.5%) were found to be malignant in follow‐up FNA and/or surgical biopsy. This scoring system may serve as a complementary tool in determining how aggressive a FNA procedure should be performed, how a FNA sample of LN should be triaged for ancillary study, and how closely a patient with lymphadenopathy should be followed up. Diagn. Cytopathol. 2013;41:1100–1106. © 2011 Wiley Periodicals, Inc.