The cytological characteristics of small cell change of dysplasia in small hepatic nodules.

Small cell change of dysplasia (SCD) is characterized as an initial step in hepatocarcinogenesis. Histopathological diagnosis is an important diagnostic procedure for nodular lesions in the liver. However, the biopsied specimen is so small that it is sometimes difficult to differentiate between regenerative nodules, dysplastic nodules, and hepatocellular carcinoma even histologically. To examine the usefulness of cytology in the differential diagnosis of hepatic nodular lesions, the cellular characteristics of SCD were evaluated using Papanicolaou staining and a micrometer. Sixty-four histologically diagnosed small nodular lesions in the liver were analyzed retrospectively. All cases were histologically classified according to the Terminology of Nodular Hepatocellular Lesions by the International Working party: hepatocellular carcinoma (HCC) (n=17); low-grade dysplastic nodule (LGDN) (n=26); high-grade dysplastic nodule (HGDN) (n=6); large regenerative nodule: (n=15). SCD was noted in all of the histological categories, and the proportion of SCD tended to be higher in W-HCC than in dysplastic nodules. Although the cellular size was the smallest in HGDN, the nuclear size was the largest in well-differentiated HCC (W-HCC). The nuclear/cytoplasmic ratio was higher in HGDN and W-HCC than in other nodular lesions. Hyperchromasia in W-HCC was obviously stronger than that in other nodules. SCD was frequently found in HGDN and W-HCC. The present study showed that detailed cytological findings of SCD are useful for differentiating HGDN from LGDN, and HGDN from W-HCC.