DNA image cytometric analysis of macroregenerative nodules (adenomatous hyperplasia) of the liver: evidence in support of their preneoplastic nature

Chronic replicative stress induced by CCl4 in TRF1 knockout mice recapitulates the origin of large liver cell changes

BACKGROUND & AIMS

Large liver cell changes (LLCC) are characterized by pleomorphic large nuclei frequently found in liver diseases as chronic viral hepatitis and liver cirrhosis. The origin of this lesion remains cryptic, but the presence of LLCC is correlated with an increased risk of hepatocellular carcinoma. Telomeric repeat binding factor 1 (TRF1) is part of the shelterin complex and is essential for telomere protection. Ablation of TRF1 induces telomere fragility and fusions and chromosomal instability.

METHODS

In this study, we addressed the role of TRF1 in liver regeneration generating a mouse model with conditional deletion of TRF1 in the liver.

RESULTS

TRF1 deletion has no deleterious effects in liver and leads to increased ploidy of hepatocytes after 2/3 hepatectomy. Mice lacking TRF1 in the liver can survive for over one year without any evidence for altered liver function. Importantly, applying chronic replicative stress by frequent carbon tetrachloride (CCl4) injections, TRF1 deleted mice undergo ploidy changes consistent with endoreduplication and develop LLCC like lesions in the liver positive for p21, Cyclin D1 and PCNA as observed in humans.

CONCLUSION

In summary, we provide mechanistic insight into the role of TRF1 in liver regeneration and provide a mouse model recapitulating the clinical features of LLCC.

Large liver cell change in hepatitis B virus-related liver cirrhosis

Large liver cell change (LLCC) refers to microscopic lesions often found in various chronic liver diseases; however, its nature is still controversial. Thirty-four formalin-fixed and 19 fresh frozen hepatitis B virus (HBV)-related cirrhosis samples were examined for the presence of LLCC, small liver cell change (SLCC), and hepatocellular carcinoma (HCC). The cell cycle checkpoint status (p21, p27, p16, Tp53), cell dynamics (proliferating cell nuclear antigen, Ki-67, terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labeling, M30), DNA damage (gamma-H2AX [H2A histone family, member X]), telomere lengths, chromosomal instability (micronuclei index), and senescence-associated beta-galactosidase (SA-beta-Gal) activity were evaluated using an in situ approach and compared to those in normal liver (n = 5) and liver with chronic cholestasis (34 cases of hepatolithiasis and three cases of primary biliary cirrhosis). In HBV-related cirrhosis, the p21, p27, and p16 cell cycle checkpoint markers were activated in normal-looking cirrhotic hepatocytes (NLCH), but diminished gradually from LLCC, SLCC, to HCC, with an increase in Tp53 expression. There was a general decrease in telomere length from NLCH, LLCC, SLCC, to HCC. Micronuclei, gamma-H2AX foci, and net cellular gain were significantly increased from normal hepatocytes, NLCH, LLCC, SLCC, to HCC. The SA-beta-Gal activity was weaker in LLCC compared to NLCH and absent in SLCC and HCC. In contrast, cholestatic LLCC showed retained expression of cell cycle checkpoint markers and decreased net cellular gain compared to adjacent normal-looking hepatocytes. HBV-related LLCC showed significantly higher Tp53 labeling index, gamma-H2AX labeling index, and micronuclei index; shorter telomere length; decreased SA-beta-Gal activity; and increased net cellular gain compared to cholestatic LLCC.

CONCLUSION

The nature of LLCC is rather heterogeneous depending on the biological setting. The characteristics of HBV-related LLCC are more consistent with dysplastic rather than merely reactive hepatocytes, whereas cholestatic LLCC more likely represents reactive change with more stringent cell cycle checkpoint control.

New perspectives and strategy research biomarkers for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide. Cirrhosis caused by hepatitis B virus, hepatitis C virus or chronic alcohol intake is associated with major risk. Systematic screening for HCC of asymptomatic patients with cirrhosis is needed for earlier detection of small tumors requiring treatment (liver transplantation, surgical resection, percutaneous techniques). The recommended screening strategy among cirrhotic patients is based on regular liver ultrasonography associated with serum alpha-fetoprotein (AFP) assay. As the performance of AFP is not satisfactory, additional tumoral markers are proposed (des-gamma-carboxyprothrombin, glycosylated AFP-L3 fraction). Currently, diagnosis of HCC in cirrhotic patients includes non-invasive tests (imaging after contrast administration, AFP assay); diagnostic biopsy is performed when imaging is limited. After treatment, tumor recurrence is assessed by regular follow-up (AFP assay and imaging). Despite the lack of accurate markers, recent developments in genomic and proteomic approaches will allow the discovery of new biomarkers for primary tumors, as well as for recurrence. This review summarizes the current state of biomarkers for screening, diagnosis and follow-up of HCC, and highlights new perspectives in the field.

Large liver cell dysplasia: a controversial entity

Large cell change (LCC) is a noncommittal term used today to indicate liver cell dysplasia of the large cell type. Dysplasia was deleted from the original definition because not enough evidence has been collected over time to support premalignancy. LCC is a microscopically well-defined lesion, usually found in cirrhosis, whose origin, natural history, and fate are still debated. Different morphologic, phenotypic, molecular and clinical studies have been performed to address the issue of the dysplastic versus reactive nature of this lesion. The aim of this review is to critically evaluate the contributions to the topic and to underline that the heterogeneity of the lesion is an important issue to be taken into account for our biological understanding of it. While LCC has important morphologic analogies in experimental liver carcinogenesis, no comparable lesions are known in solid non-liver parenchymal human tissues that morphologically feature dysplasia, but in which it is uncertain whether the lesions are reactive or preneoplastic. The debate over the lesion may be useful in learning the actual limits of morphology and how additional information can be gained by looking inside the cells.

Scirrhous changes in dysplastic nodules do not indicate high-grade status

BACKGROUND AND AIMS

Dysplastic nodules (DN) may be divided into high-grade and low-grade, and the former has been known as a precancerous or borderline lesion. Recently many morphological characteristics concerning these types of DN have been reported. In the present study we attempted to evaluate the scirrhous change in DN as an indicative feature of high-grade DN, based on the morphological and cell-kinetic analyses using immunohistochemical stains for Ki-67.

METHODS

We reviewed 35 livers with DN and selected 15 DN with scirrhous change. We stained DN-bearing sections of each case with hematoxylin and eosin, trichrome, reticulin and Perls' stain. We tried to subclassify and characterize the scirrhous change according to the fibrosis pattern. We also stained with Ki-67 immunohistochemically to assess the proliferative activity of DN with scirrhous change.

RESULTS

We found two types of scirrhous change, that is, pericellular and stellate. The pericellular type was related to the Mallory body-forming cholestatic degeneration, whereas the stellate type was associated with extensive portal fibrosis probably induced by ischemic damage. Among DN with scirrhous change, high-grade DN comprised five nodules (33%) and there were 10 (67%) low-grade nodules. There was no significant relationship between the presence or the types of scirrhous change and the grade of DN. The significant differences of Ki-67 labeling indices between types of scirrhous change were not shown in this study. We also could not find the differences between Ki-67 labeling indices of scirrhous DN (high and low grades) and those of surrounding regenerative nodules.

CONCLUSIONS

This evidence indicated that the scirrhous change in DN was not a specific feature of high-grade DN. We also found that scirrhous DN have two morphological varieties that may represent biologically different processes, that is, pericellular scirrhous type and stellate scirrhous type.

Loss of heterozygosity of chromosome 8p and 11p in the dysplastic nodule and hepatocellular carcinoma

BACKGROUND AND AIM

In hepatocarcinogenesis, both de novo and multistep pathways have been suggested, and in the latter a dysplastic nodule is the proposed precancerous lesion. But genetic changes involved in the dysplastic nodule are not well understood. In this study, we tried to determine whether allelic loss of the chromosome 8p and/or 11p could be involved in the development of the dysplastic nodule and/or hepatocellular carcinoma. Platelet-derived growth factor-receptor beta-like tumor suppressor gene (PRLTS) and deletion in liver cancer-1 tumor suppressor gene are located at 8p21.3-p22. The hepatitis B virus integration site and WT1 tumor suppressor gene are located at 11p13.

METHODS

We therefore studied loss of heterozygosity (LOH) of chromosome 8p21.3-p22 and 11p13 in 22 dysplastic nodules and 21 hepatocellular carcinomas. The samples, microdissected from paraffin-embedded tissues, were examined using a polymerase chain reaction-based LOH assay using microsatellite markers.

RESULTS

Loss of heterozygosity was detected for chromosome 8p21.3-p22 in nine (40.9%) of 22 dysplastic nodules and in eight (42.1%) of 19 hepatocellular carcinomas. D8S261, located adjacent to PRLTS, showed most frequent LOH: 28.6% in dysplastic nodule and 40.0% in hepatocellular carcinoma. Loss of heterozygosity on chromosome 11p13 was found in three (15.8%) of 19 dysplastic nodules and in six (31.6%) of 19 hepatocellular carcinomas. Loss of heterozygosity of D11S995 and D11S907 was found in 33.3% and 7.1% of dysplastic nodules, and 8.3% and 44.4% of hepatocellular carcinomas, respectively.

CONCLUSION

These results suggest that at least one putative tumor suppressor gene involved in the development and progression of hepatocellular carcinoma may be located on 8p21.3-p22 and 11p13. Particularly, PRLTS might be related to an early genetic event of hepatocarcinogenesis.

Concomitant hepatocellular adenoma and adenomatous hyperplasia in a patient without cirrhosis

AIM: Hepatocelluar adenoma (HCA) and adenomatous hyperplasia (AH) are rare benign tumors of the liver. HCA is usually found in women who use oral contraceptives. AH usually occurs in patients with liver cirrhosis. Both tumors have potential for malignant transformation.

METHODS: We described a male adult with chronic liver disease (CLD) who had been known to be a hepatitis B carrier (HBV) for years. He was found to have a space-occupying lesion with a suspicion of hepatocellular carcinoma (HCC) by abdominal ultrasonography. His α-fetoprotein (AFP) was normal. Angiographic findings were consistent with the diagnosis of HCC, he wished to avoid an operation, was treated with transcatheter hepatic arterial embolization.

RESULTS: He subsequently consented to surgery, and a right lobectomy was performed. The liver pathology disclosed HCA with nuclear dysplasia and post-embolization effects. In addition, there were multiple small foci of AH with nuclear dysplasia in the resected liver. Although he had some focal areas of cirrhosis-like change or post-embolization effect, the AH was associated only with normal liver tissue.

CONCLUSION: This case confirms that HCA and AH may resemble HCC on imaging studies, and that AH may occur in CLD in the absence of cirrhotic change.

Late-phase pulse-inversion sonography using the contrast agent levovist: differentiation between benign and malignant focal lesions of the liver

OBJECTIVE

We assessed the ability of contrast-enhanced sonography to reveal differences between benign and malignant focal hepatic lesions.

SUBJECTS AND METHODS

We examined 67 patients with focal hepatic lesions in a prospective study. The causes of the lesions were confirmed by histology, CT, MR imaging, or scintigraphy. The liver was screened for focal lesions using sonography. Thereafter, 2 g of Levovist (300 mg/mL; 1 mL/sec) was injected IV as a bolus. After a delay of at least 2.5 min without scanning, the liver was examined via three different scans using pulse-inversion sonography.

RESULTS

For the discrimination of malignant versus benign liver lesions, contrast-enhanced sonography improved sensitivity from 85% to 100% and specificity from 30% to 63%, as compared with baseline sonography. Receiver operating characteristic analysis revealed a significant improvement in this discrimination (A(z) = 0.692 +/- 0.065 at baseline sonography, A(z) = 0.947 +/- 0.037 with contrast-enhanced sonography, p < 0.001). Furthermore, a lower interobserver variability was found for contrast-enhanced sonography (weighted kappa = 0.947), as compared with baseline sonography (weighted kappa = 0.469). All lesions that had homogeneous enhancement in the late phase of Levovist enhancement were benign. In distinction, 90% of lesions without contrast enhancement in the late phase were malignant. All lesions were malignant that were isoechoic (invisible) on baseline sonography but visible because of lack of enhancement after injection.

CONCLUSION

Contrast-enhanced sonography has greater specificity and sensitivity than baseline sonography for the differentiation of benign and malignant liver lesions.

Dysplastic nodules and hepatocarcinogenesis

In the last decade, careful examination of explanted cirrhotic livers in liver transplant centers around the world has confirmed the findings of the earlier Japanese investigators: DNs (by this or any other name) represent hepatic, premalignant lesions in chronic liver disease. Careful examination of their gross and microscopic morphologies has led to the hypothesis of precirrhotic, spreading clonal expansions that are resistent to scarring, and that result in neoplastic islands of hepatic parenchyma. The resultant distinctive nodules, often marked by features suggestive of their clonality (such as increased pigment), are at increased risk for subsequent carcinomatous events, thereby giving rise to HCC. Specialized molecular and immunohistochemical studies confirm many aspects of this hypothesis. In suggesting that some aspects of DN pathophysiology are not integral to the carcinogenetic pathway (i.e., inhibition of HSC inactivation), this hypothesis serves a broader purpose, explaining the various settings in which early HCCs are found in cirrhotic explants and in wedge resections of radiographically defined lesions. Discrepancies between Japanese and non-Japanese investigations regarding dysplasia and early HCCs reflect not different biologic pathways but differences in detection, interpretation, and application of nomenclature. These differences may fade away as more international collaborative work brings investigators of diverse nationalities into regular contact, supporting movement toward a commonly acceptable nomenclature and set of diagnostic criteria. Ultimately, an understanding of the pathophysiology of these lesions, through more detailed molecular and physiologic studies, should lead to more efficient and available early detection, and perhaps chemoprevention approaches to hepatic malignancy.

Hepatocellular carcinoma: an overview

Hepatocellular carcinoma remains widely prevalent in tropical Africa and south-east Asia and is largely related to chronic hepatitis B virus (HBV) infection. Primary prevention by vaccination of infants at or near birth is effective but any reduction in tumour incidence cannot be expected for decades to come yet, even in those countries in which the necessary resources exist, as millions of adults remain chronically infected. Meanwhile, the incidence is rising in Japan, Mediterranean countries of Europe, Middle East and North Africa and in the USA, largely due to chronic hepatitis C virus (HCV) infection introduced by the indiscriminate use of unscreened blood and blood products in the recent past. Much has been learned from molecular biological studies on hepatocarcinogenesis incriminating the HBX gene of HBV, the core protein of HCV and a unique guanine to thymine transversion at codon 249 has been observed in cases due to aflatoxin exposure. The subject of precancerous lesions, notably adenomatous/dysplastic nodules and large-cell/small-cell change continues to be a source of much debate and the distinction of nodular lesions in cirrhosis from early carcinoma remains uncertain. Spontaneous regression of hepatocellular carcinoma is rare but it is probably immunologically mediated and treatment by activated T-lymphocytes may reduce recurrence rates after surgery. The positive identification of hepatocellular carcinoma by a liver-specific antibody has greatly facilitated the diagnosis in difficult cases.

Molecular changes in hepatocellular dysplastic nodules on microdissected liver biopsies

The genetic profile of dysplastic hepatocellular nodules arising in cirrhosis is poorly understood. We assessed loss of heterozygosity (LOH) and microsatellite instability (MI) in 10 dysplastic nodules (4 low-grade and 6 high-grade) with surrounding cirrhosis and in 10 hepatocellular carcinomas (HCC). Six microsatellite loci were selected and investigated on microdissected needle biopsies. Twenty-four (24.4%) informative loci showed allelic loss, while MI was seen in 3 loci only (3%). The most involved sites were located on chromosomes 4q (54.5%) and 8p (50%). LOH was documented in 16.6%, cirrhotic, 50% low-grade dysplastic nodules (LGDN), 83% high-grade dysplastic nodules (HGDN), and 70% malignant nodules. LOH at multiple loci was increasingly seen from cirrhotic to HGDN, but not from the latter to HCC. The fractional allelic loss (FAL) was significantly increased in dysplastic and neoplastic nodules as compared with cirrhosis (P <.01). The progressive accumulation of genetic changes in cirrhotic, dysplastic, and malignant hepatocellular nodules is in keeping with a multistep process of carcinogenesis; within this spectrum, HGDN can be considered advanced precursors of HCC.

Proliferating cell nuclear antigen and Ki-67 labeling in hepatocellular nodules: a comparative study

AIMS/BACKGROUND

The morphologic differential diagnosis of hepatocellular nodules (HCN) is frequently difficult and objective criteria would be useful in the categorization of such lesions. This study evaluated the proliferative activity of HCN, including regenerative, macroregenerative (MRN), cirrhotic, dysplastic, and hepatocellular carcinoma (HCC), as well as intranodular cytologic changes such as bile-stained hepatocytes, eosinophilia, clear, large cell (LCC) and small cell (SCC) change, by comparing the cellular density (CD), labeling indices (LI) and density (DP) of two proliferation markers.

METHODS

Routinely processed tissue sections from 45 HCN from 17 adult liver explants were studied by immunohistochemistry for PCNA and Ki-67 (MIB-1).

RESULTS

A progressive increase in LI from regenerative to dysplastic nodules to HCC was observed with both proliferation markers. The values of the two markers were significantly correlated (p<0.001). CD, PCNA and MIB-1 LI and DP values were significantly lower in regenerative compared to dysplastic nodules or HCC. MRNs had lower PCNA and MIB-1 LI and DP than regenerative nodules, but similar CD. There were no statistically significant differences in CD, PCNA, and MIB-1 LI and DP between dysplastic nodules and HCC, comparing high versus low grade dysplasia, or HCC smaller than 2 cm with those larger than 2 cm. The CD and proliferation indices LI and DP were higher in HCC than in the surrounding non-neoplastic parenchyma. Lesions with clear cell, eosinophilic and large cell change had CD, PCNA and MIB-1 indices similar to those of regenerative nodules, while these were lower in bile-stained hepatocellular lesions (p<0.01). SCC showed CD, PCNA and MIB-1 LI and DP similar to HCC and higher than surrounding regenerative lesions (p<0.003).

CONCLUSIONS

Our results suggest that PCNA and MIB-1 values are closely correlated in HCN. Regenerative nodules are characterized by low cellular proliferation, while dysplastic nodules are usually highly proliferative lesions and may represent an early stage in hepatocarcinogenesis. Hepatocellular lesions characterized by bile stained hepatocytes, eosinophilic, clear and large cell change have low proliferation rates and may not be significant for the development of malignancy.

Large-cell change of hepatocytes in cirrhosis may represent a reaction to prolonged cholestasis

Large-cell change of hepatocytes (LCC), also called liver cell dysplasia of large-cell type, is a set of cytologic changes comprising nuclear and cytoplasmic enlargement, nuclear pleomorphism, and multinucleation. This entity is encountered frequently on histologic or cytologic examination of specimens obtained from livers with a variety of chronic diseases and originally was thought to have a premalignant nature. Accumulating evidence, however, now suggests that LCC is merely a reactive change. Having often observed LCC in liver specimens with chronic biliary tract disease, that is, in livers where cholestasis preceded hepatocyte injury, we surmised that LCC may be a result of prolonged cholestasis. To determine whether there was any association between LCC and cholestasis, we examined microscopically a series of 400 nodules from 40 consecutive adult cirrhotic livers, resected on transplantation, and graded LCC and cholestasis semiquantitatively. LCC was present diffusely in cirrhotic nodules of 25 specimens (62.5%). Nine additional specimens (22.5%) had focal mild LCC. Usually, LCC and cholestasis occurred together, in the same cirrhotic nodules and in the same areas of nodules. There was a statistically significant association between the presence and grade of LCC and those of cholestasis (p < 0.0001; chi-square test). Within etiological categories of cirrhosis (chronic hepatitis; n = 28; alcoholic liver disease; n = 6; biliary disease: n = 6), the significance was maintained. We conclude that, in cirrhosis of different etiologies, LCC may represent a reactive change that results from prolonged cytoplasmic cholestasis.

Enzymatic cytochemistry, DNA ploidy and AgNOR quantitation in hepatocellular nodules of uncertain malignant potential in liver cirrhosis

Conventional histological examination of echo-guided biopsy specimens can be inconclusive in small nodular lesions in cirrhotic livers. We investigated the diagnostic potential of cytochemical analysis of dipeptidyl-peptidase IV (DPP IV), of image analysis of nuclear DNA content, and of interphase silver-stained nucleolar organizer regions (AgNORs) in 12 cases of small (13- to 29-mm in diameter) hepatic nodules visualized in cirrhotic patients by ultrasonography. All cases underwent an echo-guided liver biopsy at the time of detection and in none of them were histological signs of malignancy found. Characterization with the above-mentioned techniques was always done at the time of histological examination. These patients underwent a mean (+/- SD) follow-up of 27.0 (+/- 11.2) months after biopsy, with repeated ultrasound (US) examinations. In the seven patients with subsequent neoplastic growth, DPP IV score was altered in five of six; the fraction of mononucleated polyploid cells was altered in six of seven; and the AgNOR quantity exceeded the cutoff value of 4 microns2 in five of five cases. Among the five lesions whose US appearance remained unchanged during the follow-up, only one abnormality (AgNORs) was found in one case. The combined cytochemical analysis of DPP IV, nuclear DNA content, and quantitative evaluation of interphase AgNORs in biopsy samples may contribute to the differential diagnosis of hepatocellular nodules of uncertain type in the cirrhotic liver.

Arterial elements and perisinusoidal cells in borderline hepatocellular nodules and small hepatocellular carcinomas

Borderline hepatocellular nodule in the human cirrhotic liver is considered a preneoplastic lesion of hepatocellular carcinoma (HCC). However, the angiogenetic process and changes in perisinusoidal cells (fat-storing cells or Ito cells) during the borderline nodule-HCC sequence have not been investigated. We have investigated intraparenchymal arterial elements and perisinusoidal cells in normal livers, chronic hepatitis, borderline nodules and small HCC, using an immunohistochemical staining for alpha-smooth muscle actin. In normal livers, chronic hepatitis, cirrhotic nodules and large regenerative nodules, no or few arterial elements were present in the parenchyma, and alpha-smooth muscle actin-positive perisinusoidal cells were increased further. These data suggest that angiogenesis first occurs in borderline hepatocellular nodules and it gradually proceeds during the nodule to HCC sequence along with an increase in perisinusoidal cells. The demonstration of arterial elements and perisinusoidal cells may be useful for the differential diagnosis of large regenerative nodule, borderline hepatocellular nodule and small HCC.

Adenomatous hyperplasia in cirrhotic livers: histological evaluation, cellular density, and proliferative activity of 35 macronodular lesions in the cirrhotic explants of 10 adult French patients

We examined 41 consecutive cirrhotic liver explants from French patients for the presence of nodules of adenomatous hyperplasia (AH) and then analyzed these lesions, together with underlying cirrhosis (C) and associated hepatocellular carcinoma (HCC), for various histological parameters, cellular density, and proliferative activity. Thirty-five AHs were identified in 10 livers (prevalence, 24%); seven of 10 were HCV positive. Hepatocellular carcinoma was more frequent in patients with AH than in patients without. The AHs consisted of 17 ordinary (OAH) and 18 atypical (AAH) adenomatous hyperplasia lesions. There was a malignant focus in five of the 18 AAHs. Wide areas of large liver cell dysplasia were frequent in OAH but never found in AAH. Obvious steatosis was frequent in HCC but exceptional in AAH and absent in OAH. There was a significant increase in cellular density in AAH and HCC as compared with C and OAH. Proliferative cell nuclear antigen immunostaining similarly showed an increase in proliferation from OAH or C to AAH and HCC. These data suggest that, in Europe as in Japan, one pathway of hepatocarcinogenesis is a multistep process in which AAH should be considered as a premalignant lesion very close to grade I HCC, while OAH seems to correspond to a regenerative nodule with limited proliferative ability.

DNA ploidy of fibrolamellar hepatocellular carcinoma by image analysis

Twelve cases of fibrolamellar hepatocellular carcinoma (FLC) were evaluated for DNA ploidy by means of image analysis of Feulgen-stained tissue sections. All of the tumors showed a nondiploid DNA distribution (six aneuploid and six tetraploid); no diploid pattern was found. The nuclear area of the tumors (53.8 microns 2 +/- 18.0; mean +/- standard deviation) was significantly larger than that of the surrounding noncancerous livers (33.2 +/- 4.7; P < .0001). These findings suggest that DNA content in fibrolamellar carcinoma (FLC) is not directly related to the clinical behavior and that other factors may be responsible for the better prognosis of this variant of HCC.

A clinicopathologic study of adenomatous hyperplasia of the liver in 209 consecutive cirrhotic livers examined by autopsy

BACKGROUND

Adenomatous hyperplasia (AH), also called macroregenerative nodule, of the cirrhotic liver is currently considered to be a preneoplastic or early neoplastic lesion in human hepatocellular carcinogenesis.

METHODS

The authors surveyed 209 consecutive cirrhotic livers from patients who had undergone autopsy at our laboratory during the last 18 years (1974-1991), and examined the prevalence and clinicopathologic characteristics of cirrhotic livers with AH. AH was classified into two types: ordinary and atypical. Ordinary AH (OAH) is devoid of hepatocellular atypia, whereas atypical AH (AAH) consists of atypical hepatocytes equivocal as to benignity and malignancy and occasionally contains overt malignant foci.

RESULTS

A total of 123 AH were found in 45 (21.5%) of the 209 cirrhotic livers; 38 AAH were found in 12 cirrhotic livers (5.7%), and 85 OAH was found in 41 cirrhotic livers (19.6%). Nineteen AAH contained overt malignant hepatocellular foci. Comparing the first 9 years (1974-1982) with the latter 9 years (1983-1991), 4 (3.8%) of 104 cirrhotic livers harbored AAH in the first period, and 8 (7.4%) of 105 cirrhotic livers contained AAH in the latter period. Sixteen (15.4%) of 104 cirrhotic livers harbored OAH in the first period, and 25 (23.8%) of 105 cirrhotic livers contained OAH in the latter period. Etiology of the 12 cirrhotic livers with AAH was as follows: 1 was hepatitis B virus, 10 were non-A non-B hepatitis virus, and 1 was primary biliary cirrhosis. Etiology of 41 cirrhotic livers with OAH was as follows: 16 were hepatitis B virus, 18 were non-A non-B hepatitis virus, and 7 were other causes. AAH occurred commonly in mixed nodular cirrhosis, whereas OAH occurred usually in macronodular or mixed nodular cirrhosis. All 12 cirrhotic livers with AAH were associated with hepatocellular carcinoma (HCC), particularly HCC of nodular type, whereas 17 cirrhotic livers with OAH were associated with HCC and the remaining 24 cirrhotic livers with OAH were not associated with HCC.

CONCLUSIONS

These results suggest that the number of cirrhotic livers with AH is increasing gradually, and that cirrhotic livers with AAH are characterized by the association with non-A non-B hepatitis virus as well as simultaneous occurrence of HCC. Thus, AAH may be an important preneoplastic lesion in cirrhotic livers associated with non-A non-B hepatitis virus (probably hepatitis C virus).