The morphologic transition in hepatocellular carcinoma. A comparison of the individual histologic features disclosed by ultrasound-guided fine-needle biopsy with those of autopsy.

In hepatocellular carcinoma (HCC), it has been strongly suggested that as the tumor increases in size, foci of less-differentiated malignant tissues arise in the well-differentiated tumor and increase until they replace the well-differentiated tumor tissues. It has also been suggested that tumor growth is attributed to such dedifferentiation. In the current study, the individual histologic features of ultrasound-guided fine-needle biopsy specimens, taken from 12 small HCC in an early stage, were compared with those of autopsy to confirm the dedifferentiation of HCC. In all 12 cases, autopsy was performed 6 months or more after the initial biopsy. Dedifferentiation was demonstrated in 9 of 12 cases (75.0%). Most of the biopsy specimens from minute HCC were well-differentiated. All tumors that had been well-differentiated when evaluated by biopsy were found to have become moderately differentiated at autopsy. This comparative study confirmed the dedifferentiation of HCC with tumor growth.