The proliferation of atypical hepatocytes and CDT1 expression in noncancerous tissue are associated with the postoperative recurrence of hepatocellular carcinoma.

Recently, we reported that extent of proliferation of atypical hepatocytes (atypical hepatocytes) was most important histological risk factor for development of hepatocellular carcinoma (HCC) from chronic hepatitis C or liver cirrhosis. Here, we aimed to clarify whether the atypical hepatocytes in noncancerous sections is also involved in postoperative recurrence. Furthermore, we investigated significant genes involved in the atypical hepatocytes. Association between the extent of atypical hepatocytes in noncancerous tissue and postoperative recurrence was validated in 356 patients with HCC. Next, we identified putative signature genes involved in extent of atypical hepatocytes. First, atypical hepatocytes or hepatocytes other than the atypical hepatocyte in noncancerous sections of 4 HCC patients were selectively collected by laser capture microdissection (LCM). Second, the gene expression profiles of the selected hepatocyte populations were compared using Ion AmpliSeq Transcriptome Human Gene Expression Kit (Thermo Fisher SCIENTIFIC, Waltham, MA, USA) analysis. Finally, we validated the mRNA expression of the extracted genes in noncancerous frozen liver tissue from 62 patients with HCC by RT-qPCR to identify the signature genes involved in both the extent of atypical hepatocytes and postoperative recurrence. Furthermore, the extent of atypical hepatocytes and CDT1 expression in noncancerous sections from 8 patients with HCC were also validated by selectively collecting samples using LCM. The extent of atypical hepatocytes was associated with postoperative recurrence. Of the genes that showed significant differences in expression levels between two populations, the expression of the chromatin licensing and DNA replication factor 1 (CDT1) gene was most strongly associated with the extent of atypical hepatocytes and was also associated with postoperative recurrence. Furthermore, CDT1-positive cells that exhibited stronger expression resembled those morphologically considered to be atypical hepatocytes. CDT1 and Ki-67 were colocalized in the nuclei of both hepatocytes and cancer cells. The hepatocytes in noncancerous livers were not uniform in each hepatocyte population, suggesting that the accumulation of genetic abnormalities was variable. We found that the strong degree of atypical hepatocytes and high CDT1 mRNA expression represent a high carcinogenic state of the liver. Thus, we consider the evaluation of degree of these could support the personalized medicine.

Noninvasive Assessment of Liver Fibrosis: Current and Future Clinical and Molecular Perspectives.

Liver fibrosis is one of the risk factors for hepatocellular carcinoma (HCC) development. The staging of liver fibrosis can be evaluated only via a liver biopsy, which is an invasive procedure. Noninvasive methods for the diagnosis of liver fibrosis can be divided into morphological tests such as elastography and serum biochemical tests. Transient elastography is reported to have excellent performance in the diagnosis of liver fibrosis and has been accepted as a useful tool for the prediction of HCC development and other clinical outcomes. Two-dimensional shear wave elastography is a new technique and provides a real-time stiffness image. Serum fibrosis markers have been studied based on the mechanism of fibrogenesis and fibrolysis. In the healthy liver, homeostasis of the extracellular matrix is maintained directly by enzymes called matrix metalloproteinases (MMPs) and their specific inhibitors, tissue inhibitors of metalloproteinases (TIMPs). MMPs and TIMPs could be useful serum biomarkers for liver fibrosis and promising candidates for the treatment of liver fibrosis. Further studies are required to establish liver fibrosis-specific markers based on further clinical and molecular research. In this review, we summarize noninvasive fibrosis tests and molecular mechanism of liver fibrosis in current daily clinical practice.

Different Mechanisms of Action of Regorafenib and Lenvatinib on Toll-Like Receptor-Signaling Pathways in Human Hepatoma Cell Lines.

Multiple kinase inhibitors are available for patients with advanced hepatocellular carcinoma (HCC). It is largely unknown whether regorafenib or lenvatinib modulates innate immunity including Toll-like receptor (TLR)-signaling pathways in HCC. We performed real-time RT-PCR to investigate 84 TLR-associated gene expression levels and compared these gene expression levels in each hepatoma cells treated with or without regorafenib or lenvatinib. In response to regorafenib, nine and 10 genes were upregulated in Huh7 and HepG2 cells, respectively, and only C-X-C motif chemokine ligand 10 was upregulated in both cell lines. A total of 14 and 12 genes were downregulated in Huh7 and HepG2 cells, respectively, and two genes (Fos proto-oncogene, AP-1 transcription factor subunit, and ubiquitin conjugating enzyme E2 N) were downregulated in both cell lines. In response to lenvatinib, four and 16 genes were upregulated in Huh7 and HepG2 cells, respectively, and two genes (interleukin 1 alpha and TLR4) were upregulated in both cells. Six and one genes were downregulated in Huh7 and HepG2, respectively, and no genes were downregulated in both cell lines. In summary, regorafenib and lenvatinib affect TLR signaling pathways in human hepatoma cell lines. Modulation of TLR signaling pathway may improve the treatment of HCC patients with refractory disease.

Prior hepatitis B virus infection as a co-factor of chronic hepatitis C patient survival after resection of hepatocellular carcinoma.

BACKGROUND: Prior hepatitis B virus infection (PBI) may increase the risk of developing hepatocellular carcinoma (HCC), but the impact of PBI on clinical outcomes following treatment for HCC remains unknown. The aim of this study was to clarify whether PBI affects clinical outcomes after liver resection for hepatitis C virus (HCV)-related HCC by retrospective cohort study. METHODS: PBI patients were defined as those negative for hepatitis B surface antigen and positive for anti-hepatitis B core antibody. Surgical outcomes of HCV-related HCC patients with PBI were compared to those without PBI. Survival of patients with non-B non-C HCC with and without PBI were also compared. RESULTS: In the HCV group, the median overall survival of 165 patients with PBI was 4.7 years (95% confidence interval [CI], 3.9-5.9), and was significantly shorter compared with 263 patients without PBI (6.6 years [5.3-9.8]; p = 0.015). Conversely, there was no significant difference in recurrence-free survival between the two groups (1.8 years [95% CI, 1.4-2.0] vs 2.0 years [1.7-2.3]; p = 0.205). On Cox proportional hazards regression model, independent factors for overall survival were PBI (hazard ratio 1.38 [95% CI, 1.02-1.87]; p = 0.033), multiple tumors (p = 0.007), tumor size (p = 0.002), and liver cirrhosis (p <  0.001). On the other hand, in the non-B non-C HCC group, both the median overall survival (6.5 years [95% CI, 4.8-7.1]) and recurrence-free survival (2.4 years, [95% CI, 1.5-3.3]) in 104 patients with PBI were not significantly different from those (7.5 years [5.5 - NA; p = 0.932]; and 2.2 years [1.7-2.7; p = 0.983]) in 213 patients without PBI. CONCLUSIONS: PBI and HCV in conjunction with each other affect the survival of patients that have undergone resection for HCC.

Possible association of arrestin domain-containing protein 3 and progression of non-alcoholic fatty liver disease.

The prevalence of non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) is increasing worldwide. Several effective drugs for these diseases are now in development and under clinical trials. It is important to reveal the mechanism of the development of NAFLD and NASH. We investigated the role of arrestin domain-containing protein 3 (ARRDC3), which is linked to obesity in men and regulates body mass, adiposity and energy expenditure, in the progression of NAFLD and NASH. We performed knockdown of endogenous ARRDC3 in human hepatocytes and examined the inflammasome-associated gene expression by real-time PCR-based array. We also examined the effect of conditioned medium from endogenous ARRDC3-knockdown-hepatocytes on the apoptosis of hepatic stellate cells. We observed that free acids enhanced the expression of ARRDC3 in hepatocytes. Knockdown of ARRDC3 could lead to the inhibition of inflammasome-associated gene expression in hepatocytes. We also observed that conditioned medium from endogenous ARRDC3-knockdown-hepatocytes enhances the apoptosis of hepatic stellate cells. ARRDC3 has a role in the progression of NAFLD and NASH and is one of the targets for the development of the effective treatment of NAFLD and NASH.

Follow-up Results of HCV GT2 Patients After Sofosbuvir/Ribavirin Therapy: Careful Attention to Occurrence of HCC.

BACKGROUND: We examined treatment the efficacy and data on long-term outcomes in real-world Japanese patients infected with hepatitis C virus (HCV) genotype 2 treated with 12-week sofosbuvir/ribavirin combination therapy. PATIENTS AND METHODS: In a total of 86 patients who were treated with sofosbuvir/ribavirin, sustained virological response (SVR) rates and long-term-outcomes were retrospectively analyzed. RESULTS: The adherence to this combination therapy was 98.8%. The rates of SVR at week 24 (SVR24) achieved with this treatment according to the 'intention-to-treat' and 'per-protocol' analyses were 89.5% and 96.2%, respectively. Two patients who experienced relapse did not have any previously reported resistance-associated substitutions in the HCV non-structural protein 5B (NS5B) polymerase region. We did not observe any patients who experienced late relapse but did observe that 50% and 1.3% of patients with and without a previous history of hepatocellular carcinoma (HCC), respectively, developed HCC after achieving SVR24 (with a mean follow-up period of 2.7±0.8 years). CONCLUSION: Patients with SVR should be carefully followed-up to screen for the occurrence of HCC, although it is infrequent.

Exosomes and Hepatocellular Carcinoma: From Bench to Bedside.

As hepatocellular carcinoma (HCC) usually occurs in the background of cirrhosis, which is an end-stage form of liver diseases, treatment options for advanced HCC are limited, due to poor liver function. The exosome is a nanometer-sized membrane vesicle structure that originates from the endosome. Exosome-mediated transfer of proteins, DNAs and various forms of RNA, such as microRNA (miRNA), long noncoding RNA (lncRNA) and messenger RNA (mRNA), contributes to the development of HCC. Exosomes mediate communication between both HCC and non-HCC cells involved in tumor-associated cells, and several molecules are implicated in exosome biogenesis. Exosomes may be potential diagnostic biomarkers for early-stage HCC. Exosomal proteins, miRNAs and lncRNAs could provide new biomarker information for HCC. Exosomes are also potential targets for the treatment of HCC. Notably, further efforts are required in this field. We reviewed recent literature and demonstrated how useful exosomes are for diagnosing patients with HCC, treating patients with HCC and predicting the prognosis of HCC patients.

Apoptosis and non-alcoholic fatty liver diseases.

The number of patients with nonalcoholic fatty liver diseases (NAFLD) including nonalcoholic steatohepatitis (NASH), has been increasing. NASH causes cirrhosis and hepatocellular carcinoma (HCC) and is one of the most serious health problems in the world. The mechanism through which NASH progresses is still largely unknown. Activation of caspases, Bcl-2 family proteins, and c-Jun N-terminal kinase-induced hepatocyte apoptosis plays a role in the activation of NAFLD/NASH. Apoptotic hepatocytes stimulate immune cells and hepatic stellate cells toward the progression of fibrosis in the liver through the production of inflammasomes and cytokines. Abnormalities in glucose and lipid metabolism as well as microbiota accelerate these processes. The production of reactive oxygen species, oxidative stress, and endoplasmic reticulum stress is also involved. Cell death, including apoptosis, seems very important in the progression of NAFLD and NASH. Recently, inhibitors of apoptosis have been developed as drugs for the treatment of NASH and may prevent cirrhosis and HCC. Increased hepatocyte apoptosis may distinguish NASH from NAFLD, and the improvement of apoptosis could play a role in controlling the development of NASH. In this review, the association between apoptosis and NAFLD/NASH are discussed. This review could provide their knowledge, which plays a role in seeing the patients with NAFLD/NASH in daily clinical practice.

Association of mRNA expression of iron metabolism-associated genes and progression of non-alcoholic steatohepatitis in rats.

BACKGROUND: Excess iron is associated with non-alcoholic steatohepatitis (NASH). RESULTS: mRNA expression of duodenal cytochrome b, divalent metal transporter 1, ferroportin 1, hepcidin, hephaestin and transferrin receptor 1 in liver were higher in high fat, high cholesterol-containing diet (HFCD) group than in normal diet (ND) group. mRNA levels of divalent metal transporter 1 and transferrin receptor 1, which stimulate iron absorption and excretion, were enhanced in small intestine. Epithelial mucosa of small intestine in HFCD group was characterized by plasma cell and eosinophil infiltration and increased vacuoles. Iron absorption was enhanced in this NASH model in the context of chronic inflammation of small intestinal epithelial cells, consequences of intestinal epithelial cell impairment caused by HFCD. Iron is transported to hepatocytes via portal blood, and abnormalities in iron absorption and excretion occur in small intestine from changes in iron transporter expression, which also occurs in NASH liver. Knockdown of hepcidin antimicrobial peptide led to enhanced heavy chain of ferritin expression in human hepatocytes, indicating association between hepcidin production and iron storage in hepatocytes. CONCLUSIONS: Iron-related transporters in liver and lower/upper portions of small intestine play critical roles in NASH development. METHODS: Expression of iron metabolism-related genes in liver and small intestine was analyzed in stroke-prone spontaneously hypertensive rats (SHR-SP), which develop NASH. Five-week-old SHR-SP fed ND or HFCD were examined. mRNA and protein levels of iron metabolism-related genes in liver and small intestine from 12- and 19-week-old rats were evaluated by real-time RT-PCR and immunohistochemistry or Western blot.

Persistent Hepatic Inflammation Plays a Role in Hepatocellular Carcinoma After Sustained Virological Response in Patients with HCV Infection.

Objective: Hepatitis C virus (HCV) infection has long been treated with interferon therapy (IFN). Currently, more than 90% of IFN-treated patients show a sustained virological response (SVR) when also treated with ribavirin and/or a protease inhibitor. Histological inflammation and fibrosis improve in IFN-treated patients, which indicates HCV clearance. IFN also reduces the incidence of hepatocellular carcinoma (HCC). However, a small proportion of patients with SVR develop HCC. To investigate the causes of hepatic carcinogenesis after SVR, we compared the liver histological findings before IFN to those after the development of HCC. Patients and methods: In total, 602 patients infected with type C chronic hepatitis or with liver cirrhosis who received IFN therapy during the period from 1992 through 2015 were included in this study. We assessed 14 of the 287 patients who achieved an SVR. Results: HCC was diagnosed by computed tomography, angiography or liver biopsy. The longest time from the SVR until HCC detection was 16.5 years, and the mean was 7.2±4.6 years. Nine of the 14 patients underwent surgery and one radiofrequency ablation. The histological findings of 10 patients were available for comparison. The comparison of the histological findings before treatment with those after the HCC diagnosis revealed an amelioration of liver fibrosis and other inflammatory changes. All ten patients showed improvements in fibrosis and steatosis. However, we observed that mild inflammatory change persisted from 1.8 years to 16.5 years after the confirmation of SVR in all cases. Conclusion: We suspect that persistent histological inflammation is one of the factors contributing to hepatocarcinogenesis (i.e., HCC development) even after successful treatment.

Diabetes mellitus not an unfavorable factor on the prognosis of hepatitis C virus-related hepatocellular carcinoma.

AIM: Diabetes mellitus (DM) is a potential risk factor for hepatocarcinogenesis, especially in patients with hepatitis C virus (HCV) infection. We aimed to elucidate whether DM influences the surgical outcomes of patients with hepatocellular carcinoma (HCC). METHODS: Our patients were routinely controlled to keep urinary glucose excretion to less than 3.0 g/day before surgery, and the serum glucose level under 200 mg/dL after surgery. The surgical outcomes and postoperative complications of 112 patients with HCV-related HCC with DM (DM group) were compared to those of 112 propensity-matched patients without DM (non-DM group). RESULTS: After a median follow-up of 3.2 years (range, 0.2-11.3 years), the median overall (5.2 years; 95% confidence interval, 3.8-6.5 years) and recurrence-free survival (2.2 years; 1.7-2.9 years) in the DM group were not significantly different from those (6.3 years; 5.4-7.1 years, P = 0.337; and 2.2 years; 1.7-3.6 years, P = 0.613) in the non-DM group. The independent factors related to overall survival were the background liver (hazard ratio, 2.06; 95% confidence interval, 1.27-3.39, P = 0.014) and tumor differentiation grade (2.07; 1.14-4.05, P = 0.015). Thirty-two patients (28.5%) in the DM group and 32 patients (28.5%) in the non-DM group had morbidities after operation, with no significant difference between the groups (P = 1.000). Furthermore, postoperative control status of DM did not affect the prognostic outcome. CONCLUSION: Diabetes mellitus does not affect the surgical outcomes of patients with HCV-related HCC, and it is not an unfavorable factor when selecting candidates for liver resection of HCC.

Involvement of Ornithine Carbamoyltransferase in the Progression of Chronic Hepatitis C and Liver Cirrhosis.

Background: The involvement of serum ornithine carbamoyltransferase (OCT) in the progression of chronic hepatitis and liver cirrhosis is unclear. Methods: A total 256 patients with chronic hepatitis C and 5 healthy controls were examined. Serum OCT concentrations were measured by enzyme-linked immunosorbent assay. Serum OCT concentrations were compared with serum cytokine and chemokine levels, and with disease severity and development of hepatocellular carcinoma (HCC). Results: The median OCT concentrations were 21.8 ng/ml for healthy controls, 36.7 ng/ml for F0 stage disease, 48.7 ng/ml for F1 stage, 77.9 ng/ml for F2 stage, 104.8 ng/ml for F3 stage, and 121.4 ng/ml for F4 stage. OCT concentrations were correlated with aspartate aminotransferase, alanine aminotransferase, γ-glutamyl transpeptidase, platelet counts, indocyanine green retention rate at 15 min, prothrombin times, the molar ratio of branched chain amino acids to tyrosine, and tyrosine. Furthermore, there were significant correlations among OCT concentrations and IP10 and IL18 levels. There were weak correlations between serum OCT concentrations and liver histology. The cumulative incidence of HCC in the high-OCT concentration group (≥75.3 ng/ml) was higher than that in the low-OCT concentration group. Conclusion: The measurement of serum OCT concentration may provide a useful marker of disease severity, and thus could be a useful marker for a high risk of HCC occurrence.

Clinical correspondence to hepatocellular carcinoma-related lesions with atypical radiological pattern.

In patients at risk of hepatocarcinogenesis, tumors are frequently detected with atypical radiological patterns related to hepatocellular carcinoma (HCC) on imaging studies. Despite their high potential for malignancy, whether to resect such lesions immediately is controversial. Based on histological findings, patients with non-enhanced tumors or enhanced tumors without washout were divided into two groups: those with tumors that should be treated containing well, moderately, and poorly differentiated HCC (Group 1), and those that can be observed containing early HCC, hepatocellular adenoma, focal nodular hyperplasia, dysplastic nodules, and regenerative nodules (Group 2), and we elucidated the clinical correspondence to these tumors. Seventy-two patients had a single tumor with atypical radiological pattern: 39 patients had HCC (Group 1), while 33 patients had benign tumors or early HCC (Group 2). Among nine baseline variables, serum α-fetoprotein (AFP) level in Group 1 (median, 13.2 ng/mL; range, 0.6-5881.6) was significantly higher than that in Group 2 (5.6 ng/mL; 0.8-86.3, P = 0.003). The cut-off value of AFP was 36.4 ng/mL for prediction of Group 1, and the median overall and recurrence-free survival periods of 23 patients in the high-AFP (≥ 36.4 ng/mL) group (5.3 years; 95%CI, 2.1 - N.A. and 1.6 years; 0.5-2.2) were significantly shorter than those of the 49 patients in the low-AFP (< 36.4) group (7.5 years; 7.5 - N.A., P = 0.047, and 2.8 years; 1.9-3.3, P = 0.001). Taken together, HCC-related tumors with an atypical radiological pattern could be observed unless serum AFP level is elevated.

Steatosis influences the clinical profiles and long-term outcomes of interferon-treated chronic hepatitis C and liver cirrhosis patients.

Objective: This study aimed to assess the relationship between steatosis and long-term outcomes of patients with chronic hepatitis C (CH) and liver cirrhosis (LC). Patients and methods: The study population included 282 subjects with CH or LC who underwent liver biopsy at our institute. All patients achieved a sustained virological response (SVR) to interferon (IFN). Clinical characteristics, including age, gender and body mass index (BMI), were compared. The liver biopsy specimens of all patients were examined and scores were assigned to indicate the severity of each of the following features: inflammatory cell infiltration in the periportal, parenchymal and portal areas; F (fibrosis) stage; portal sclerotic change; perivenular fibrosis; pericellular fibrosis; bile duct damage; hepatic steatosis. Results: Of the 282 patients, 112 (39.7%) were free of steatosis. The other 170 patients (60.3%) had steatosis. The blood biochemical parameters of the patients with hepatic steatosis were significantly poorer than those of patients free of steatosis. Inflammatory cell infiltration and F stage were both significantly more severe in patients with than in those without steatosis. The incidences of hepatocellular carcinoma differed significantly between the two groups. However, the incidences of hepatocellular carcinoma did not differ significantly between the groups with BMI above and below 25. Conclusion: We consider hepatic steatosis to potentially affect the blood biochemical parameters and clinical profiles of Japanese patients with CH due to hepatitis virus type C. Patients with this form of CH showed favorable clinical responses to IFN. Furthermore, fibrosis and steatosis appear to affect the long-term outcomes of these patients. However, BMI alone cannot be used to predict HCC development.

Contrast-enhanced ultrasonographic findings of serum amyloid A-positive hepatocellular neoplasm: Does hepatocellular adenoma arise in cirrhotic liver?

Hepatocellular adenoma (HCA) was recently classified into four pathological subtypes. There have been few studies describing the findings of contrast-enhanced ultrasonography (CEUS) of each type. Our case concerns a 78-year-old man who had undergone routine medical check-ups for hepatitis C for 11 years. Abdominal ultrasonography showed a 28 mm, hypo-echoic mass in the segment 4 of the liver. His integrating amount of drinking was 670 kg convert into ethanol. CEUS with Sonazoid demonstrated mild uniform hypo-enhancement with inflow of microbubbles from the periphery of the tumor in the arterial phase, and heterogeneously hypo-enhancement in the post vascular phase. Because the mass increased in size within 3 mo, a well differentiated hepatocellular carcinoma was suspected, and hepatic resection was performed. Microscopic findings showed homogeneous cell proliferation with low grade atypia, infiltration of inflammatory cells, ductular reactions, fatty deposit in part, and sinusoidal dilation. Immunohistochemistry revealed geographic positive for serum amyloid A (SAA), focal positive for glutamine synthetase, diffuse and strong positive for C-reactive protein, and positive for liver-type fatty acid binding protein. These pathological features corresponded to that of an inflammatory HCA. However, we could not make a clear diagnosis, because HCAs were defined as not to arise in cirrhotic liver. Finally, this tumor was diagnosed as a SAA positive hepatocellular neoplasm.

Onset of Tuberculosis from a Pulmonary Latent Tuberculosis Infection during Antiviral Triple Therapy for Chronic Hepatitis C.

A 62-year-old man was diagnosed with the onset of tuberculosis (Tb) from a pulmonary latent tuberculosis infection (LTBI) during triple therapy with pegylated interferon α2a, ribavirin, and telaprevir for a chronic hepatitis C infection in 2013 before interferon (IFN)-free anti-viral therapy was introduced in Japan. A liver biopsy before IFN treatment revealed the presence of epithelioid cell granulomas (ECGs). IFN may also be employed for chronic hepatitis B infection and malignant tumors, thus, special attention must be paid to the development of Tb from a LTBI when ECGs are observed before treatment. It is also necessary to review the significance of the liver biopsy.

[A case of acute progressive primary inflammatory fibrosarcoma of the retroperitoneum].

A 70-year-old man with liver cirrhosis presented to us with abdominal distention. Computed tomography revealed a giant retroperitoneal tumor. Examination of a biopsy specimen led to a diagnosis of primary inflammatory fibrosarcoma of the retroperitoneum. However, disease progression was rapid, and the patient died 6 weeks after the onset of the disease. Autopsy revealed that the tumor arose from the retroperitoneum and infiltrated the omentum and mesentery. Prognosis of inflammatory fibrosarcoma is poor if resection is incomplete. Establishment of treatment for unresectable cases is necessary.

Improving recognition of hepatic perivascular epithelioid cell tumor: Case report and literature review.

A 58-year-old man presented with the chief complaint of abdominal bloating and was incidentally found to have a liver tumor. As diagnostic imaging studies could not rule out malignancy, the patient underwent partial resection of segment 3 of the liver. The lesion pathologically showed eosinophilic proliferation, in addition to immunohistochemical positivity for human melanoma black 45 and Melan-A, thereby leading to the diagnosis of a hepatic perivascular epithelioid cell tumor (PEComa). A PEComa arising from the liver is relatively rare. Moreover, the name 'PEComa' has not yet been widely recognized, and the same disease entity has been called epithelioid angiomyolipoma (EAML), further diminishing the recognition of PEComa. In addition, PEComa imaging findings mimic those of malignant liver tumors, and clinically, this tumor tends to enlarge. Therefore, a PEComa is difficult to diagnose. We conducted a systematic review of PEComa and EAML cases and discuss the results, including findings useful for differentiating perivascular epithelioid cell tumors from malignant liver tumors.

Pathological evidence of the cause of spontaneous regression in a case of resected hepatocellular carcinoma.

A 67-year-old man presented for an evaluation after experiencing right hypochondrial pain lasting for two months. Abdominal ultrasonography showed a hepatic tumor in the right liver and extremely mild hepatic steatosis. The imaging findings indicated that the tumor (43 mm in size) was ischemic, and the lesion was surgically resected and examined. The histopathological findings demonstrated 95% necrosis with moderately differentiated hepatocellular carcinoma (HCC). The diagnosis was HCC with spontaneous regression. There was also pathological evidence of thrombus formation in the peripheral arteries and portal veins. In addition, the non-cancerous regions of the liver were diagnosed as exhibiting non-alcoholic steatohepatitis. The pathological findings obtained after resection of the HCC lesion showed spontaneous regression.