Virchows Arch (2005) 447: 996–999
DOI 10.1007/s00428-005-0042-z

CASE REPORT

Katsuaki Sato . Yoshimichi Ueda . Keiichi Ueno .
Kazuya Okamoto . Hideaki Iizuka . Shogo Katsuda

Hepatocellular carcinoma and nonalcoholic steatohepatitis
developing during long-term administration of valproic acid
Received: 25 February 2005 / Accepted: 6 July 2005 / Published online: 17 August 2005
# Springer-Verlag 2005

Abstract We report a case of hepatocellular carcinoma
(HCC) arising in nonalcoholic steatohepatitis (NASH). The
patient, a 64-year-old man, was incidentally found to have
multiple tumors in the liver when admitted for pneumonia.
He had been obese, had been receiving a standard dose of
valproic acid since clipping surgery for subarachnoid
hemorrhage 17 years previously, and had not consumed
any alcohol since the surgery. Laboratory data revealed
moderate hyperlipidemia and no evidence of diabetes
mellitus, hepatitis B or C infection. The patient died of
hepatic insufficiency, and an autopsy was performed. A
tumor, a maximum of 13 cm in diameter, grossly occupied
the entire left lobe and one third of the right lobe of the
liver. Histologically, moderately differentiated HCC was
found with foci of poorly differentiated HCC. The nontumorous area showed NASH with moderate bridging
fibrosis, without interface hepatitis, hemochromatosis, or
copper accumulation. In this patient, obesity, hyperlipidemia, and long-term treatment with valproic acid could
have all been associated with induction of NASH. The
present case suggests that HCC could develop in noncirrhotic NASH liver, and that chronic inflammation in
itself could be an important risk factor in the development
of HCC.
K. Sato (*) . Y. Ueda . S. Katsuda
Department of Pathophysiological and Experimental Pathology,
Kanazawa Medical University,
1-1 Daigaku, Uchinada, Kahoku,
Ishikawa, 920-0293, Japan
e-mail: sato-k@kanazawa-med.ac.jp
Tel.: +81-76-2188119
Fax: +81-76-2862484
K. Ueno
Department of Surgical Oncology,
Kanazawa Medical University,
Ishikawa, Japan
K. Okamoto . H. Iizuka
Department of Neurosurgery,
Kanazawa Medical University,
Ishikawa, Japan

Keywords Hepatocellular carcinoma . Nonalcoholic
steatohepatitis . Nonalcoholic fatty liver disease .
Valproic acid

Introduction
Nonalcoholic steatohepatitis (NASH) is part of the spectrum
of nonalcoholic fatty liver disease (NAFLD), clinically
related with metabolic syndrome [3], and is histologically indistinguishable from alcoholic hepatitis [1]. Although
the natural history of NASH has yet to be fully clarified,
simple hepatic steatosis is nonprogressive, whereas nearly
20% of NASH cases may slowly progress to cirrhosis [8],
and distinctive cases with hepatocellular carcinoma (HCC)
arising in NASH have recently been reported [6, 13, 16, 17,
19, 23]. Valproic acid (VPA) is a worldwide antiepileptic
drug, which occasionally causes idiosyncratic hepatotoxicity, but the association of VPA with steatohepatitis and
HCC has not been determined [1]. This is the first report of
HCC arising in moderately fibrosing NASH liver in a patient receiving long-term VPA administration.

Clinical history
A 64-year-old man was admitted to hospital with a diagnosis of pneumonia. CT scans of the lower chest incidentally detected multiple tumors in the liver. The patient
had received VPA (800 mg per day, standard dose) since
clipping surgery for subarachnoid hemorrhage 17 years
previously. He had been a chance drinker but had consumed no alcohol since the surgery 17 years previously.
His family history was unremarkable. Laboratory data
had irregularly shown slightly elevated liver enzymes. At
the time of admission, total cholesterol (261 mg/dl) and
triglyceride (175 mg/dl) levels were moderately increased,
and the serum levels of α-fetoprotein (18,270 ng/ml) and
PIVKA-II (487 AU/ml) were highly elevated. The HbA1C
value was within the normal range. Hepatitis B surface

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Results

antigen and anti-hepatitis C virus antibody in the serum
were negative. Neither liver biopsy nor chemotherapy was
performed. The patient died of hepatic insufficiency 1 year
after admission, and an autopsy was performed 2 h after
death.

At autopsy; the patient was obese, 82 kg in weight (BMI
34.1 kg/m2), and 155 cm in height. The skin showed an
icteric discoloration. Massive ascitic fluid (6,000 ml) was
observed. The liver weighed 1,500 g, and the gross appearance showed that the tumor measured a maximum of 13 cm
in diameter. The tumor occupied the entire left lobe and one
third of the right lobe of the liver (Fig. 1). Histologic examination revealed that the tumor consisted mainly of
moderately differentiated HCC, with a focal pseudoglandular pattern (Fig. 2a). A poorly differentiated HCC component was also observed in some parts of the tumor. HCC
cells with marked fatty deposition were also observed
focally (Fig. 2b). In the background of the tumor, both
micro- and macrovesicular steatosis was apparent, especially in the centrilobular area. Ballooned liver cells with
Mallory bodies and infiltrates of neutrophilic cells were
commonly observed around the central veins (Fig. 2c).
Spotty necrosis was scattered throughout the lobules. Perivenular and pericellular fibroses were also manifested.
Bridging fibrosis between the central veins and portal tracts
was evident, but regenerative nodules had not formed
(Fig. 2d). There was no evidence of interface hepatitis, hemochromatosis, or copper accumulation.

Materials and methods

Discussion

The autopsy specimens were fixed in 10% formalin and
embedded in paraffin. Tissue sections of 4 μm in thickness
were stained for hematoxylin and eosin as well as the
Azan-Mallory method.

This case is interesting as HCC developed in a noncirrhotic NASH liver, and the patient had received longterm VPA therapy. The liver, in the presence of NASH,
may have the potential to progress to cirrhosis and liver

Fig. 1 Macroscopic appearance of the cut surface of the autopsied
liver. The main tumor occupies the entire left lobe and approximately one third of the right lobe of the liver. There are also multiple
nodules in the right lobe

Fig. 2 Histologic features of the
tumor. a The tumor consists
mainly of moderately differentiated hepatocellular carcinoma
with a focal pseudoglandular
pattern. Hematoxylin and eosin,
×100. b There are hepatocellular
carcinoma cells with marked
fatty depositions. Hematoxylin
and eosin, ×200. c Ballooned
liver cells with Mallory bodies
and infiltrates of neutrophilic
cells are frequently observed
around the central vein. Hematoxylin and eosin, ×400.
d Bridging, perivenular, and
pericellular fibrosis are diffusely
observed in the non-tumorous
area, but regenerative nodules
are not visible. Azan-Mallory,
×40

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Table 1 Clinicopathologic features of cases with hepatocellular carcinoma and nonalcoholic steatohepatitis
Case

Author [reference]

Age/Sex

Background disease

HCC histology

Tumor size (cm)

Liver histology

1
2
3

Powell et al. [17]
Cotrim et al. [6]
Zen et al. [23]

57/F
62/M
72/F

DM
DM, OB
DM

Orikasa et al. [16]
Shimada et al. [19]
Shimada et al. [19]
Shimada et al. [19]
Shimada et al. [19]
Shimada et al. [19]
Shimada et al. [19]
Mori et al. [13]
Present case

67/F
66/F
69/F
69/F
72/M
63/M
56/M
76/M
64/M

DM
DM
ND
DM, OB
OB
HL, OB
DM
DM, OB
OB, HL, Drug

ND
3
1.3
1.0
1.4
2.6
1.5
1.5×2
2.5
3
2
1–6, M
1.9
13, M

Cirrhosis
Cirrhosis
Cirrhosis

4
5
6
7
8
9
10
11
12

ND
ND
Mod
Wel
Dys
Clear-cell
Mod
Wel
ND
Wel
Wel
Mod
Wel
Mod

Pre-cirrhosis
Cirrhosis
Cirrhosis
Cirrhosis
Cirrhosis
Cirrhosis
Cirrhosis
Cirrhosis
Fibrosis

F female, M male, DM diabetes mellitus, OB obesity, HL hyperlipidemia, HCC hepatocellular carcinoma, ND not described, Mod
moderately differentiated, Wel well differentiated, Dys dysplasia, M multiple

failure, thereby promoting the development of HCC [17].
Although a large number of HCCs have been reported to
arise in cryptogenic cirrhosis in patients with risk factors
for NAFLD [4], the accurate incidence of HCC in NASH
remains undetermined [3]. Half of the patients with cryptogenic cirrhosis have pathological and clinical characteristics consistent with NAFLD and account for 13% of HCC
cases [12]. Some cases of cryptogenic cirrhosis have histologic features of burned-out NASH [15]. Cases of HCC
that developed in NASH are not uncommon; however, to
our knowledge, there have been only 11 well-documented
cases reported in the literature [6, 13, 16, 17, 19, 23].
Table 1 summarizes the clinicopathologic features of the
cases of HCC developing in NASH, including the present
case. The histology of the background liver was cirrhosis in
ten cases, and pre-cirrhosis in only one case. The present
case is unique in that the tumor developed in a noncirrhotic liver. More than 80% of patients with HCC have
underlying cirrhosis [18], and cirrhosis itself is recognized
as a common factor promoting HCC. However, the remaining cases of HCC, approximately 20%, can develop in
a non-cirrhotic liver. There is a report of an animal study in
which a new inbred mouse strain, fatty liver Shionogi,
spontaneously developed fatty liver and HCC in the noncirrhotic liver [21]. Although it remains uncertain whether
cirrhosis is required for the development of HCC, at least,
this case indicates that HCC can arise in a non-cirrhotic
NASH liver.
Reactive oxygen species (ROS), products due to oxidative stress, activate lipid peroxidation, and TGF-β induction, can stimulate fibrosis [1]. On the other hand, the major
products of lipid peroxidation, malondialdehyde, and 4hydroxynonenal, act as DNA mutagens [11], which might
be associated with the initiation of HCC [5]. Because
inflammation is a principal source of ROS, chronic inflammation can be a risk factor for various carcinomas [7].

Recently, mice with somatic inactivation of the nrf1 gene in
the liver have been reported to spontaneously develop
HCC in a background of non-cirrhotic liver, and oxidative
injury had been present before tumor development [22].
These results suggest that ROS overproduced in NASH
liver could trigger carcinogenesis as well as fibrosis, and
that cirrhosis is not essential for the development of HCC.
Major risk factors for primary NASH are: obesity, type 2
(non-insulin-dependent) diabetes mellitus, and hyperlipidemia [1]. Hyperinsulinemia is an underlying factor in these
conditions. NAFLD was found to be present in almost
90% of patients with obesity; approximately 25% of whom
had NASH [14]. About 50% of patients treated with VPA,
which is speculated to modulate insulin secretion and
systemic metabolism, experienced weight gain [2]. The present patient was obese and presented moderate hyperlipidemia, without evidence of diabetes mellitus. Obesity
might be influenced by VPA and be indirectly associated
with the development of HCC through the induction of
NASH.
Causes of secondary NASH include: drugs, nutritional
factors, and metabolic or genetic disorders [1]. VPA, a
short fatty acid derivative, can cause hepatic microvesicular steatosis, which is related to insulin resistance [1].
VPA also impairs mitochondrial β-oxidation, a frequent
mechanism underlying drug-induced steatohepatitis [9].
Derangements of mitochondrial β-oxidation generate an
overproduction of ROS, leading to enhanced lipid peroxidation and cytokine production similar to primary (obesity-related) NASH [1]. These pathogenetic factors may act
as an enhancement of HCC development. Contrarily, VPA
has shown anticancer activity mediating inhibition of histone deacetylases and an induction of carcinoma cell differentiation [10, 20]. However, the antiproliferative effect
on carcinoma cells of VPA and the relationship between
VPA treatment and HCC development are not evident.

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