Early hepatocellular carcinoma that develops within macroregenerative nodules: Growth rate depicted at serial MR imaging

PURPOSE: To assess by means of magnetic resonance (MR) imaging the growth rate of early hepatocellular carcinoma (HCC) that develops within macroregenerative nodules. MATERIALS AND METHODS: Serial MR imaging was performed in five patients with six macroregenerative nodules that demonstrated a 'nodule-within-nodule' pattern (small intranodular focus). The diameter and volume increases of the internal foci at different time intervals were estimated. Average doubling time (DT) was then calculated. RESULTS: The tiny loci within macroregenerative nodules exhibited rapid growth, with average DTs of 29 weeks for diameter and 9.5 weeks for volume. HCC was proved histopathologically in all five patients. CONCLUSION: HCC which manifests initially as a small focus within a macroregenerative nodule, has the potential for rapid growth. This growth rate should be considered when plans are formulated for follow-up and/or treatment.