[Early detection of primary liver cancer--diagnosis of small liver cancer by needle aspiration biopsy].

: Small liver cancer is defined as a solitary hepatocellular carcinoma (HCC) with a diameter less than 2cm. To detect liver cancer as early as possible, patients with liver cirrhosis are screened by ultrasound scanning. Pathological diagnosis in needle aspiration biopsy materials is needed because of low positivity of imaging other than ultrasound scanning. Pathological features are different from those of classical hepatocellular carcinoma. Most of the small HCCs are characterized by the following features: (1) increased cellularity, (2) increased nucleus/cytoplasm ratio, (3) irregular thin trabecular pattern, (4) pseudoglandular or acinar structures, (5) increased staining affinity (eosinophilic/basophilic), (6) frequent fatty change, and (7) residue of the portal tract. Capsules of HCCs, 1-1.5 cm in diameter, are formed. Before the formation of capsules, cancerous cells show a replacing growth pattern. Two cases of small HCC are presented, and these characteristic features are explained.