Neoplasia IV

Features of benign tumours

  • Macro (round)
  • Symmetrical, organised
  • Homogenous - cut surface is uniform
  • Encapsulated - means legion is slow growing, usually benign
  • Normal N:C (nucleus: cytoplasm) ratio

Features of malignant tumours

  • Look nasty/not natural
  • Irregular
  • Infiltrative
  • Destructive
  • Heterogenous: as tumour progresses, it begins to consist of more diverse cells
    • May denote haemorrhage or necrosis
  • Nuclear: cytoplasmic ratio increased
  • Pleomorphism: cells grow in multiple shapes and sizes
  • Hyperchromatia: darkly stained nuclei, usually due to increased DNA content

Classification of tumours

Epithelium

  • Carcinomas
Glandular
  • Benign - adenoma
  • Malignant - adenocarcinoma
Squamous
  • Benign - papilloma
  • Malignant - SCC

Bladder

  • Transitional cell carcinoma (TCC)

Mesenchyme (connective tissues)

  • Malignant - sarcomas

Fat

  • Benign - lipoma
  • Malignant - liposarcoma

Bone

  • Benign - osteoma
  • Malignant - osteosarcoma

Cartilage

  • Benign - enchondroma
  • Malignant - chondrosarcoma

Skeletal muscle

  • Benign - rhabdomyoma
  • Malignant - rhabdomyosarcoma

Smooth muscle

  • Benign - leiomyoma
  • Malignant - leiomyosarcoma

Nerves

  • Benign - neurofibroma, schwannoma
  • Malignant - malignant peripheral nerve sheath tumour

Blood vessels

  • Benign - haemangioma
  • Malignant - angiosarcoma, Kaposi’s sarcoma

CNS

  • Gliomas - range from benign version of a tumour to a malignant version

Melanocytic

  • Freckle - ephelis
  • Mole - naevus
  • Malignant - melanoma

Blood

  • All malignant - already systemic
  • Leukaemias, lymphomas

Genetics and tumours

  • Cytogenetics: large changes, look at chromosomes (FISH)
  • Molecular genetics: small changes e.g. oncogenes

Staging and grading of tumours

  • Stage: how far tumour has spread
    • Well differentiated tumour which has grown slowly but been present for ages = high stage
    • Aggressive rapidly growing cancer caught early = low stage
  • Grade: how bad
    • The degree of cytological atypia (differentiation)
    • Well differentiated = low grade (cells look like they should)
    • Poorly differentiated = high grade (difficult to tell what the cell of origin is)