Accuracy of cytology vs. microbiopsy for the diagnosis of well-differentiated hepatocellular carcinoma and macroregenerative nodule - Definition of standardized criteria from a study of 100 cases

OBJECTIVE: To determine the accuracy of ultrasound (LTS)-guided fine needle aspiration (FNA) for the diagnosis of well-differentiated hepatocellular c arcinoma (wd HCC) and macroregenerative nodule (MRN) and to identify the mo st useful cytologic and histologic criteria to distinguish between those tw o diagnoses. STUDY DESIGN: Cytologic and histologic specimens of 50 wd HCC and 50 MRN we re reviewed blindly and the diagnosis compared to the final clinical diagno sis. Twenty-eight cytologic and 25 histologic criteria were examined and su bjected to statistical analysis. RESULTS: Among 100 cases studied, the final diagnosis was available for 43. In those 43 cases, combining analysis of cytologic and histologic specimen s, the sensitivity of US-guided FNA was of 75% and the specificity 100%. I Cytologic analysis was better than isolated histologic analysis, with It se nsitivity of 75% vs. 68%, respectively. Sensitivity of cytologic diagnosis teas lower for smaller nodules and for those located in poorly accessible h epatic segments. With the use of stepwise logistic regression analysis, fou r cytologic features (increased nuclear/cytoplasmic ratio, cellular monomor phism, nuclear crowding, loss of bile duct cells) and four histologic featu res (increased nuclear/cytoplasmic ratio, decreased Kupffer cells, cellular monomorphism, increased trabeculae thickness) were identified as predictiv e of HCC. CONCLUSION: This study demonstrated that FNA with US guidance can provide a n accurate diagnosis of wd HCC and MRN. The limiting factor of the method i s sampling error, especially for small HCC and nodules located in poorly ac cessible hepatic segments.