Definition/General

Introduction:
-Hepatocellular carcinoma (HCC) is the most common primary liver malignancy
-Accounts for 85-90% of primary liver cancers
-Major cause of cancer death worldwide
-Strong association with chronic liver disease
-FNAC shows characteristic hepatocellular differentiation.
Origin:
-Arises from hepatocytes (liver parenchymal cells)
-Develops in setting of chronic liver disease and cirrhosis
-Multistep carcinogenesis from dysplastic nodules
-Results from chronic inflammation and regeneration
-Viral hepatitis major etiological factor.
Classification:
-WHO classification based on differentiation grade
-Well-differentiated (Grade 1)
-Moderately differentiated (Grade 2)
-Poorly differentiated (Grade 3)
-Undifferentiated (Grade 4)
-Variants: fibrolamellar, scirrhous, clear cell.
Epidemiology:
-Major global health problem with 782,000 deaths annually
-Male predominance (M:F = 3:1)
-Peak incidence 5th-6th decades
-High incidence in Asia-Pacific region
-India: 20,000+ new cases annually.

Clinical Features

Presentation:
-Right upper quadrant pain (most common)
-Hepatomegaly and abdominal mass
-Ascites and jaundice
-Weight loss and cachexia
-Underlying cirrhosis signs
-Portal hypertension complications.
Symptoms:
-Abdominal pain (60-90%)
-Abdominal distension
-Weight loss (50-80%)
-Early satiety
-Jaundice (20-40%)
-Peripheral edema
-Bone pain (metastases)
-Paraneoplastic syndromes.
Risk Factors:
-Hepatitis B virus (most important globally)
-Hepatitis C virus (major in developed countries)
-Alcohol-related cirrhosis
-NAFLD/NASH
-Aflatoxin exposure
-Hemochromatosis
-Alpha-1-antitrypsin deficiency.
Screening:
-Alpha-fetoprotein (AFP) and ultrasound every 6 months
-High-risk patients (cirrhosis, chronic hepatitis)
-CT/MRI for further characterization
-EUS-FNAC for tissue diagnosis when imaging non-diagnostic.

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Gross Description

Appearance:
-Variable appearance depending on background liver
-Single large mass (50%) or multiple nodules
-Tan-yellow to green coloration
-Areas of hemorrhage and necrosis
-May show central scarring.
Characteristics:
-Soft to firm consistency
-Variegated cut surface
-Hemorrhage and necrosis common
-Bile production may be evident (green discoloration)
-Central stellate scar in fibrolamellar variant.
Size Location:
-Size ranges from small nodules to massive tumors
-Multifocal disease common (70%)
-Right lobe more commonly involved
-May involve both lobes
-Portal/hepatic vein invasion frequent.
Multifocality:
-Multifocal disease in 70% of cases
-Satellite nodules around main tumor
-May represent intrahepatic metastases
-Multinodular type common in cirrhotic livers.

Microscopic Description

Histological Features:
-Malignant cells with hepatocellular differentiation
-Trabecular, pseudoacinar, solid patterns
-Increased nuclear-cytoplasmic ratio
-Prominent nucleoli
-Bile production
-Sinusoidal invasion
-Loss of reticulin framework.
Cellular Characteristics:
-Large polygonal cells resembling hepatocytes
-Abundant eosinophilic cytoplasm
-Round to oval nuclei with coarse chromatin
-Prominent nucleoli
-Intracytoplasmic bile (pathognomonic)
-Mallory-Denk bodies occasional.
Architectural Patterns:
-Trabecular pattern (most common)
-Pseudoacinar pattern with bile in center
-Solid pattern (poorly differentiated)
-Compact pattern
-Scirrhous pattern (rare)
-Macrotrabecular pattern.
Grading Criteria:
-Edmondson-Steiner grading: Grade I (well-differentiated, resembles hepatocytes)
-Grade II (moderate differentiation)
-Grade III (poor differentiation)
-Grade IV (undifferentiated)
-Nuclear grade and architectural pattern.

Immunohistochemistry

Positive Markers:
-Hepatocyte Paraffin 1 (HepPar1) - highly specific
-Arginase-1 - highly sensitive and specific
-Glypican-3 - useful in poorly differentiated cases
-Alpha-fetoprotein - variable (30-60%)
-Albumin in-situ hybridization
-CD10 canalicular pattern.
Negative Markers:
-CK7, CK19 typically negative (bile duct markers)
-CEA negative (polyclonal)
-TTF-1 negative
-CDX2 negative
-Chromogranin A negative
-MOC-31 negative.
Diagnostic Utility:
-HepPar1 and Arginase-1 diagnostic combination
-Glypican-3 distinguishes from adenoma
-CD10 canalicular staining supportive
-Helps distinguish from cholangiocarcinoma and metastases
-Combined panel essential.
Molecular Subtypes:
-Proliferation class (S1-S3 based on gene expression)
-Non-proliferation class
-CTNNB1-mutated subclass
-Immune class
-Recently defined by molecular profiling for targeted therapy.

Molecular/Genetic

Genetic Mutations:
-TERT promoter mutations (54% of HCC)
-CTNNB1 mutations (27%)
-TP53 mutations (21%)
-AXIN1 mutations (8%)
-RB1 alterations
-ARID1A mutations
-MYC amplification.
Molecular Markers:
-Alpha-fetoprotein (AFP) elevated in 60-70%
-AFP-L3 (lectin-reactive AFP)
-Des-gamma-carboxy prothrombin (DCP/PIVKA-II)
-Glypican-3 overexpression
-Genomic instability common.
Prognostic Significance:
-CTNNB1 mutations associated with better prognosis
-TP53 mutations indicate aggressive behavior
-Satellite lesions worsen prognosis
-Vascular invasion major prognostic factor
-Molecular classification guides treatment.
Therapeutic Targets:
-Sorafenib (multi-kinase inhibitor)
-Lenvatinib (first-line therapy)
-Regorafenib (second-line)
-Pembrolizumab (immunotherapy)
-Cabozantinib
-Ramucirumab (anti-VEGFR2).

Differential Diagnosis

Similar Entities:
-Cholangiocarcinoma (intrahepatic)
-Metastatic carcinoma to liver
-Hepatocellular adenoma
-Combined hepatocellular-cholangiocarcinoma
-Angiomyolipoma
-High-grade dysplastic nodule.
Distinguishing Features:
-HCC: HepPar1, Arginase-1 positive
-HCC: Trabecular pattern, bile production
-Cholangiocarcinoma: CK7, CK19 positive
-Metastases: Organ-specific markers
-Adenoma: Glypican-3 negative.
Diagnostic Challenges:
-Poorly differentiated HCC vs metastases
-Well-differentiated HCC vs adenoma
-Combined tumors with mixed features
-Fibrolamellar variant vs focal nodular hyperplasia
-Sampling adequacy in FNAC.
Rare Variants:
-Fibrolamellar carcinoma (young patients, no cirrhosis)
-Scirrhous HCC (abundant fibrosis)
-Clear cell variant
-Pleomorphic giant cell
-Sarcomatoid HCC
-Combined HCC-cholangiocarcinoma.

Sample Pathology Report

Template Format

Sample Pathology Report

Complete Report: This is an example of how the final pathology report should be structured for this condition.

Specimen Information

FNAC from liver mass, [location], [number] passes

Clinical Information

AFP: [level] ng/ml, Background: [cirrhosis/normal]

Adequacy

Specimen is adequate for diagnosis

Cellular Findings

Highly cellular smears showing [malignant hepatocytes]

Cell Morphology

Large polygonal cells with [cytoplasmic] and [nuclear] features

Hepatocellular Features

Shows hepatocellular differentiation with [bile/trabecular pattern]

Background

Background liver shows [cirrhosis/normal hepatocytes]

Immunocytochemistry

HepPar1: [result], Arginase-1: [result], CK7: [result]

Final Diagnosis

FNAC liver: Hepatocellular carcinoma, [grade]