Focal nodular hyperplasia with concomitant hepatocellular carcinoma: a case report and clonal analysis

Abstract

This report describes a hepatocellular carcinoma (HCC) with concomitant focal nodular hyperplasia (FNH) in a 56 year old Chinese man. There were two well circumscribed tumours measuring 3 x 2.5 x 2 cm and 2 x 1.5 x 1.5 cm. The larger mass was grey and soft with a small area of bleeding and necrosis and an intact capsule. The smaller mass was yellow and had no capsule. Clonal analysis was carried out to clarify the relation between the HCC and the adjacent FNH. The clonal analysis was based on the methylation pattern of the polymorphic X chromosome linked androgen receptor gene (HUMARA). In FNH, after HpaII digestion, the allelic bands showed two well defined peaks. The intensity of the two peaks in the DNA from cirrhotic tissue did not differ significantly, consistent with a random pattern of X chromosome inactivation. However, in HCC, after HpaII digestion, the allelic bands differed significantly in intensity. Therefore, there was a typical polyclonal pattern of inactivation in FNH but the HCC was interpreted as being monoclonal.

Figure 1

The liver tumour was composed of two different masses. The right mass was grey and soft with a small area of bleeding and necrosis. The left mass was yellow.

Figure 2

The yellow portion of the liver tumour was composed of large hyperplastic hepatocytes with short fibrous septa containing malformed vessels and bile ductules. Haematoxylin and eosin stain; original magnification, ×100.

Figure 3

The grey portion of the liver tumour showed a classic hepatocellular carcinoma arranged in trabecular and acinar patterns. Haematoxylin and eosin stain; original magnification, ×200.

Figure 4

Clonal analysis. The results of the HUMARA assay in cirrhotic liver tissue (A) without digestion or (B) after HpaII digestion. Peaks 1 and 2 correspond to the two distinct alleles of the liver tissue. The results in focal nodular hyperplasia (FNH) (C) without digestion or (D) after HpaII digestion. DNA from cirrhotic liver tissue and FNH showed the same methylation pattern with and without HpaII digestion, consistent with a polyclonal pattern. The results in hepatocellular carcinoma (HCC) (E) without digestion or (F) after HpaII digestion. In HCC, a significant decrease of allele 2 was seen after HpaII digestion, consistent with a monoclonal pattern.