Epithelial tumours

• Epithelia line the internal and external surfaces of the body
• Epithelium is defined as resting on a basement membrane

Carcinoma

• Carcinoma: specific term for epithelial malignancy
• Risk increases with age due to long term accumulation of environmental risk factors
  • If an older person has a malignant tumour it is epithelial until proven otherwise e.g. brain lesions are metastatic carcinoma until proven otherwise
  • Therefore, carcinoma is very uncommon in children - children are most likely to suffer malignancy of blood cells, brain cells and mesenchymal cells

Disease progression

• Characterised by local growth
• Spread via haematogenous and lymphatic routes

Lymphatic route

• Local lymph node involvement is common
• Different patterns of spread for different tumours
  • e.g. testicular cancer spreads to the para-aortic lymph nodes (rather than to the groin) - links to embryological development

Haematogenous route

• Lung primary - metastases to bone, brain, adrenal and the liver
• Breast cancers similar to lung primary
• GI malignancies – liver (other sites are rare)
• Prostate cancer can metastasize anywhere

Mesenchymal tumours

• Soft tissue tumours - bone, cartilage, fibrous tissue, fat, smooth muscle, skeletal muscle, nerves, blood vessels etc.
• Sarcomas = malignant