Pathology histology - Hepatocellular carcinoma (HCC)

Pathology histology

Normal liver

Liver with hepatocellular carcinoma

HCC - Tumor area

• Surrounding areas are normal (has cells with lipofuscin in cytoplasm)

• This area is a tumour surrounded by a capsule

• Tumour area shows loss of normal sinusoid pattern

• Normal structures can be seen amongst the tumour portion (e.g. bile ducts)

• Enlarged nuclei (high nuclei/cytoplasm area)

• No portal triads

• Less pink, more blue → Enlarged nuclei + Immune cells

• Nuclei are very close → Less cytoplasm

• Large variations of nuclei size

HCC - Capsule surrounding tumour area

• Collagen type I

• Encapsulates tumor area

• Outside pretty much normal liver, inside is tumour and immune cells

• Formed by the expansion of the tumour

HCC - Immune cells

Normal portal triad

Liver with HCC stained with anti-Ki67/anti-vimetin

• Brown → Ki67-positive → Proliferating cells

• Red → Vim-positive → Cells of mesenchymal origin (e.g. fibroblasts, endothelial cells, smooth muscle) or showing mesenchymal differentiation

• In carcinomas, vimentin positivity often indicates epithelial–mesenchymal transition (EMT), which is associated with increased invasiveness and metastatic potential - NOT seen in this case

• Mesenchymal cells should not be found in liver because liver cells are from endoderm origin - Presence of them here indicates carcinoma

• Roughly around 5% of nuclei are brown, rest are blue - Gives us an indication of fast the tumor is growing (in this case slow growing → better prognosis)

Normal liver stained with GoS

• Black → Collagen type III

• Purple/brown → Collagen type I

Liver with HCC stained with GoS

HCC stained with GoS - Capsule around tumor area

• Purple → Collagen type I

HCC stained with GoS - Tumor area

• Loss of a normal sinusoidal pattern (less black collagen type III)

• No portal triads or similar surrounded by purple collagen type I