Neoplasia IV

• Methods to obtain material for diagnosis:

  • Fine needle aspirate biopsy
  • Tru-cut core needle biopsy
  • Forceps biopsy
  • Incisional biopsy
  • Complete removal lump/excision
• Specimen referral to the laboratory:

  • Requisition form contains patient details, nature of specimen, and clinical details
  • Specimens usually received in formalin; occasionally received fresh for specific tests
  • On receipt in the lab, each specimen pot and requisition form are checked for accuracy
  • Each case is given a specific identification number
• Fine needle aspirate biopsy:

  • Contains cells only (cytology); architecture cannot be assessed
• Tru-cut core needle biopsy:

  • Shows cells and stroma, allowing architecture assessment (histology)
  • Pathologists prefer Tru-cut biopsies for tissue architecture and immunohistochemical stains
• Wax Block:

  • Used to create slides stained with H&E
  • Haematoxylin stains nuclei purple/blue
  • Eosin stains cytoplasm and extracellular matrix pink
• Haematoxylin:

  • Derived from the tree Haematoxylon campechianum
  • Used historically as a fabric dye and for medical purposes
• Eosin:

  • Discovered in 1874 by Heinrich Caro
  • Used as a dye and in medical staining
• Tumour excision margins:

  • Inking the sample for orientation
  • Deep and radial margins inked blue
• Tumour grading:

  • Reflects how closely a tumour resembles its normal tissue counterpart
  • Grades include well-differentiated, moderately differentiated, and poorly differentiated
• Tumour staging:

  • pTNM staging system used for tumour resections
  • Determines patient treatment and prognosis based on T (Tumour), N (Nodes), and M (Metastasis)
• Special stains:

  • Periodic acid-Schiff (PAS) and Alcian blue for identifying specific tissue characteristics
  • Masson-Fontana for detecting melanin in malignant melanoma
  • Congo Red for identifying amyloid in glomeruli