**2.1 Clinical features of HCC**

Early HCC are asymptomatic and are usually picked up during surveillance imaging. Classic clinical triad of right upper quadrant abdominal pain, palpable lump and weight loss is noted in 90% of the symptomatic patients [4]. New onset of abdominal pain and abdominal distension due to ascites are common in patients with underlying liver cirrhosis [5, 6]. Rapid worsening of portal hypertension indicates invasion of portal vein by tumor leading to tumor thrombosis [6]. Generalized weakness, anorexia and weight loss are common symptoms noted in 90%, 74% and 55% patients respectively [7]. Catastrophic presentation in the form of tumor rupture, hemoperitoneum and shock occurs in 3–15% of cases [8]. Hepatomegaly with irregular or nodular surface is common finding in nearly 84% cases [7]. Arterial bruit is present in minority of cases (2.6%) [9]. Ascites in HCC is most commonly due to underlying decompensated cirrhosis or due to tumor invasion of hepatic veins, portal vein or peritoneum and is often hemorrhagic [9]. Paraneoplastic manifestations of HCC include type B hypoglycemia due to increased production of insulin like growth factors by tumor, hypercalcemia, hypertension, carcinoid syndrome, clubbing, polycythemia, porphyria, thyrotoxicosis, migratory thrombophlebitis, watery diarrhea, sexual changes like feminization, gynecomastia [9].

#### **2.2 Imaging diagnosis of hepatocellular carcinoma**

Almost 90% of HCC develop on the background cirrhotic liver [10]. Regenerative nodules form in cirrhotic livers obtain majority of blood supply from portal vein, like the normal liver parenchyma. As the nodule progresses from regenerative to dysplastic and then into HCC, there is shift in blood supply from portal vein to hepatic artery [10]. Hence HCC obtains majority of the blood supply from hepatic artery. This forms the basis of diagnosis of HCC by non-invasive methods using multiphase computed tomography scan (CT) and magnetic resonance imaging (MRI). Radiology forms the cornerstone in diagnosis of HCC in cirrhotic liver. Non-invasive methods are applied to nodule ≥1 cm in cirrhotic liver due to high pretest probability [10].

Technical details related to machine, required images and additional images to be taken while evaluating liver nodule are mentioned in **Table 1**.

## *2.2.1 Typical appearance of hepatocellular carcinoma in cirrhotic liver on multiphase CT or MRI scans include*


*Hepatocellular Carcinoma: Diagnosis and Surveillance DOI: http://dx.doi.org/10.5772/intechopen.99839*


#### **Table 1.**

*Technical details, required images and additional images to be obtained while evaluating liver space occupying lesion [11].*


#### *2.2.2 Comparison of multiphase CT and MRI with extracellular contrast agents performance in detecting HCC*

**Table 2** shows comparative performance of multiphase CT and MRI in HCC with various sizes [12].

For all sizes and tumors with <1 cm MRI with extracellular contrast agents appears to be more sensitive than CT scan with comparable specificity and diagnostic odds. Hence for small lesions MRI with extracellular contrast agents may be preferred modality over CT scan. Having said this availability, cost, longer scan times, more technical complexities, expertise, several patient factors like ascites, difficulty in breath holding, claustrophobia may limit its use as the first investigation for evaluation of liver lesion in cirrhotic patients. CT scan on the other had is technically relatively simple, less number and short duration of sequences, widely available and less costly than MRI. However, radiation exposure is the disadvantage of the CT scan. Hence multiple factors like availability, cost, patient related factors, tumor size, radiation are necessary to be considered to choose between CT scan and MRI as first investigation for evaluation of liver lesion [12].

#### *Hepatocellular Carcinoma - Challenges and Opportunities of a Multidisciplinary Approach*


#### **Table 2.**

*Comparative performance of multiphase CT and MRI in HCC with various sizes.*

#### *2.2.3 Role of MRI with hepatocyte specific contrast agents in diagnosis of HCC*

This technique uses Gadoxetic acid as a contrast agent. Approximately 50% of the administered dose is taken up by hepatocyte and excreted into the bile ducts and remaining half was excreted by kidneys [13]. Images are taken in two phases: Transitional phase taken at 2–5 minutes after contrast agent and hepatobiliary phase taken after 20 minutes of contrast injection [13]. Lesions with functional hepatocytes take up the contrast in hepatobiliary phase and appear hyperintense. Those without functional hepatocytes like high grade dysplastic nodules or HCC do not take the contrast in hepatobiliary phase and appear hypointense compared to background liver parenchyma [13]. These early HCC or high grade dysplastic nodules may not show typical arterial hyperenhancement resulting in missing some of the early HCC lesions. Addition of hepatobiliary phase to conventional dynamic MRI sequences increases likelihood of identifying malignant nodules and reduces the risk of overlooking malignant lesions [13–15]. Signal intensity of lesion on hepatobiliary phase is also a prognostic factor with hypointense lesions on hepatobiliary phase which are non-hypervascular, non-HCC have a higher risk of progression to typical HCC as compared to those lesions which are iso- or hyper-intense [16, 17].

#### *2.2.4 Role of contrast enhanced ultrasound in diagnosis of HCC*

It is performed with intravenous injection of a microbubble contrast agent. Real-time imaging is performed continuously for the 1st minute to capture the arterial phase. This is followed by intermittent scanning every 30–60 seconds for up to about 5 minutes to evaluate washout [11]. Typical appearance of HCC on Contrast enhanced ultrasound (CEUS) shows non rim arterial phase hyperenhancement and washout in delayed phase >60 seconds to differentiate it from mass forming cholangiocarcinoma which show early washout. It requires expertise and cannot scan entire liver at a time like CT or MRI [11]. CEUS has low sensitivity for detection of lesion as compared to CT and MRI but has higher specificity as compared to CT and MRI especially for small nodules (< 20 mm) 92.9% vs. 76.8% vs. 83.2% [18]. CEUS as second imaging modality has highest specificity 76.8% (after MRI) and 70.7% (after CT) for diagnosis of HCC [19].

#### *2.2.5 Liver imaging reporting and data system (Li-RADS)*

Liver imaging reporting and data system (Li-RADS) provides standardization for hepatocellular carcinoma (HCC) imaging. Li-RADS defines eight unique *Hepatocellular Carcinoma: Diagnosis and Surveillance DOI: http://dx.doi.org/10.5772/intechopen.99839*

diagnostic categories LR 1 to 5, LR-M for malignant but not specific for HCC, LR-TIV for tumor in vein, LR-TR for treated lesion, based on imaging appearance that reflect the probability of HCC or malignancy with or without tumor in vein. Term LR-NC (non-categorizable observation) is used when observation that cannot be meaningfully categorized due to lack of one or more major criteria. LI-RADS criteria are to be applied for liver nodules in cirrhotic livers and lesion >1 cm. **Table 3** describes the each Li-RADS category and risk of HCC and non-HCC malignancy [11].

LI-RADS is not applicable for liver lesions in noncirrhotic liver, vascular liver diseases, sinusoidal obstruction syndrome, chronic inflow obstruction and hereditary hemorrhagic telangiectasia.

### *2.2.6 Role of Fluorodeoxyglucose positron emission tomography (FDG-PET) in diagnosis of HCC*

FDG uptake is seen only in 40% of patients with HCC, so FDG-PET scan is not useful for diagnosis of HCC [20]. Uptake on 18F-FDG-PET has some potential prognostic significance and is associated with poor prognosis, increased serum alpha-fetoprotein and vascular invasion. Therefore, it may facilitate the selection of patients for surgical resection or liver transplantation [21].

### *2.2.7 Diagnosis of portal vein thrombosis- tumoral vs. non-tumoral (bland thrombus)*

Cirrhosis without HCC is associated with portal vein thrombosis with prevalence ranging from 1% in compensated cirrhosis to as high as 25% in patients with advanced liver disease requiring liver transplantation [22]. Macrovascular invasion of the portal vein is a major prognostic factor frequently seen in HCC. Portal vein thrombosis may create diagnostic dilemma in patients with cirrhosis and HCC. Presence of arterial phase hyperenhancement, diffusion weighted MRI with high b values, venous expansion with diameter > 23 mm, thrombus in continuity with parenchymal HCC are the findings which point towards the diagnosis of tumoral portal vein thrombosis [23, 24].

#### **2.3 Pathological diagnosis of hepatocellular carcinoma**

HCC diagnosis in cirrhotic liver is based on imaging criteria mentioned above. However biopsy is required in patients with vascular liver diseases, non-cirrhotic livers, inconclusive radiological investigations, elevation of CA 19.9 or carcinoembryonic antigen (CEA) and liver lesion without HCC risk factors [24]. Samples for histological diagnosis of HCC can be obtained by image guided (ultrasound / CT scan) biopsy sometimes by diagnostic laparoscopy. Resected specimens and explants after liver transplants need evaluation for resection margin and histological assessment [24].

#### *2.3.1 Gross appearance*

HCC takes three forms nodular, massive or diffusely infiltrating type. Nodular form is often associated with liver cirrhosis. Massive form is associated with satellite nodules and has potential to rupture. Diffuse infiltrating type causes involvement of large part of liver and its vascular structures mainly portal vein, and is associated with poor prognosis [25].


#### **Table 3.**

*LI-RADS criteria with description of terminologies, risk of overall malignancy and risk of HCC. [APHE – Arterial phase hyperenhancement, TIV- tumor in vein].*

#### *2.3.2 Microscopic appearance*

Microscopically HCC can be well differentiated, moderately differentiated, undifferentiated and progenitor cell. Most common variety is well differentiated type. It can

#### *Hepatocellular Carcinoma: Diagnosis and Surveillance DOI: http://dx.doi.org/10.5772/intechopen.99839*

be of trabecular type or acinar type (pseudoglandular type). Malignant hepatocytes are polygonal with large hyperchromatic nuclei. Bile production is present. Moderately differentiated HCC can be of solid, scirrhous, sarcomatoid and clear cell varieties. Solid type tumor shows small hepatocytes with areas of necrosis, inconspicuous fibrous tissue and absent bile production. In scirrhous variety abundant connective tissue stroma is noted separating hepatocytes. Clear cell variety has cells having high glycogen content. Undifferentiated HCC has pleomorphic cells with variable sized nuclei. Progenitor cell HCC have their origin from stem cells of liver. These tumors may appear similar to HCC or mixed cholangiohepatocellular carcinoma [25]. On biopsy specimens differentiation of small HCC from high grade dysplastic nodules is challenging. Diagnosis of HCC needs to be supplemented with three marker panel as recommended by International Consensus Group of Hepatocellular Neoplasia and the World Health Organization. This is because features of interstitial and vascular invasion can be missed on biopsy specimens. Combination of HSP70 (HSPA7), glypican 3 (GPC3), and glutamine synthetase (GS) has sensitivity and specificity of 72% and 100%, respectively in surgically resected specimens and its specificity is validated in biopsy specimens [26, 27]. Several immunohistochemical markers useful in diagnosis of hepatocellular carcinoma include Arginase-1 which is most sensitive and specific marker for hepatocellular differentiation. Hepatocyte paraffin-1 (Hep Par-1) has both sensitivity and specificity greater than 80% for HCC. Polyclonal carcinoembryonic antigen (pCEA) shows typical canalicular pattern and has sensitivity of 92% and 88% for well differentiated and moderately differentiated HCC [28].

HCC is heterogenous tumor in pathogenesis, behavior, phenotype and has different genetic signatures as described by recent studies. As mentioned above several different subtypes are described. 5th edition of world health organization classification of digestive system tumors integrates histopathologic features and molecular signatures of these tumors. **Table 4** shows morphological features, molecular signatures of different HCC subtypes as per 5th Edition of WHO Classification of Digestive system tumors [29, 30].

#### *2.3.3 Risks associated with biopsy of the lesion*

Biopsy is associated with risk of bleeding in 3–4% cases and severe bleeding requiring transfusion in 0.5% cases [31]. Risk of needle track seeding of tumor cells is about 2.7% [32]. Sampling errors can occur for small lesions <2 cm [33].

#### **2.4 Role of tumor markers in diagnosis of HCC**

Tumor markers are the substances which can be measured in cells, tissues, body fluids, indicate presence of cancer and help in prognostication. Ideal tumor marker should be highly sensitive and specific so as to diagnose lesions early HCC. Alfa fetoprotein (AFP) is used since long time for surveillance and diagnosis of hepatocellular carcinoma [34]. Now with identification of new molecular signatures, our understanding of pathological processes involved in HCC is improved leading development of newer biomarkers. This section will through light on old and new tumor markers and their utility in diagnosis of HCC [34].

#### *2.4.1 Alfa fetoprotein (AFP)*

AFP is a glycoprotein produced by fetal liver. After birth levels of AFP fall and its synthesis is repressed in adult life. It is expressed under some pathological conditions like chronic liver disease, cirrhosis, HCC, germ cell tumors and cholangiocarcinoma [35]. It is the most extensively studied biomarker for surveillance and diagnosis of


#### **Table 4.**

*Shows morphological features, molecular signatures of different HCC subtypes as per 5th edition of WHO classification of digestive system tumors.*

HCC. AFP is elevated in nearly 70% patients with HCC. When cut-off value of 20 ng/ ml is used AFP has sensitivity of 59.9% and specificity of 93% while at the cut-off value of 200 ng/ml sensitivity drops to 22% and specificity of 100% [35, 36]. AFP can be falsely elevated in patients with viral infections like hepatitis B and C. Positive predictive value of AFP in diagnosing HCC in patients with viral etiologies and non-viral etiologies was 70% vs. 94% in one study using cut-off of 20 ng/ml [34]. AFP also has prognostic significance with values ≥400 ng/ml have higher tumor burden, bilobar involvement, tumoral portal vein thrombosis and diffuse and massive variety of tumors [35]. Limitations of AFP measurement include false negative in small HCC and 30% of large tumors do not have elevated levels [35]. False positive in chronic liver disease, cirrhosis, HCC, germ cell tumors and cholangiocarcinoma [34, 35]. AFP-L3 glycoform of AFP is detected in approximately 35% of <3 m size HCC. Cut-off level of 15% has sensitivities ranging from 75%–96.9% and specificities of 90–92% [35]. Higher levels of AFP-L3 are associated with worse liver function, poor histology and large tumor mass and portal vein invasion [35].

## *2.4.2 Glypican-3*

It is proteoglycan in plasma membrane. It produced by tumor cells but not elevated in non-HCC liver diseases. It can be detected in 40–53% of HCC patients and 33% of HCC patients with negative for both AFP and PIVKA-II. Addition of Glypican-3 measurements to AFP improves sensitivity from 50–72% [34, 35].

### *2.4.3 Des-gamma-carboxyprothrombin or protein induced by vitamin K absence or antagonist II (PIVKA-II)*

It is abnormal product from liver carboxylation disturbance during the formation of thrombogen [34, 35]. It is overproduced in HCC patients. Sensitivity and specificity of PIVKA-II at the cut-off level 40 mAU/ml is 51.7% and 86.7% while at the cut-off value of 125 mAU/mL in discriminating HCC from nonmalignant hepatopathy sensitivities and specificities were 89% and 86.7% [37, 38]. In combination AFP-L3, AFP and DCP achieved 60.6% sensitivity and 100% specificity while DCP combined with AFP alone increased sensitivity from 65–87%, but specificity dropped from 84–69% [39, 40]. Japanese clinical guidelines recommend the combined use of PIVKA-II and AFP for the diagnosis of HCC, management of high-risk population, and prognosis of anticancer treatment [41].
