Morphological clues for the diagnosis of small hepatocellular carcinomas.

Histological features of 44 cases of small hepatocellular carcinoma (HCC) were examined and compared with those of large regenerative nodules. The highly differentiated type of HCC most often occurred in nodules which were less than 2 cm in diameter. Noticeably, in 9 out of 15 such cases (60.0%), tumour cells were arranged in trabeculae of almost normal thickness (normotrabecular pattern). These trabeculae, however, showed variable nuclear crowding, occasional microacinar formation, and increase in cytoplasmic basophilia. It is emphasized that the presence of this triad may be a very reliable indicator for the histological identification of early HCC, especially in examining limited material such as a biopsy specimen. However, cellular and structural atypia becomes more prominent in nodules which are larger than 2 cm.