Docstoc

Neoplasia Terminology

Document Sample
Neoplasia Terminology Powered By Docstoc
					 Neoplasia

Dr. Raid Jastania
      Neoplasia: Terminology
• Cancer is the 2nd cause of death in the US
• Neoplasia is “new growth”
• Neoplasm is an abnormal mass of tissue the
  growth of which exceeds and is
  uncoordinated with that of the normal
  tissues and persists after cessation of stimuli
  (By Willis)
         Neoplasia: Terminology
•   Loss of normal growth (growth autonomy)
•   Loss of normal differentiation
•   Transformation
•   Tumor: swelling, mass of tissue
•   Oncology: Study of tumors
•   Benign vs Malignant
    – Benign: localized, not fatal
    – Malignant: cancer, invasive, metastasize, fatal
    Neoplasia: concept of origin
• Zygote – cells – tissues – organs – human
• DNA, genetic material, genes are the present in all
  the cells of the body
• Cells differ in gene expression
• Type of cells (based on genes expressed)
   – Control of growth
   – Differentiation
• Monoclonality is the basis of neoplasia
• Tumor progression, divergent differentiation
                  Nomenclature
• Benign tumors
  – Suffix “–oma” is added to the cell type
     •   Fibrous: fibroma
     •   Cartilage: chondroma
     •   Bone: osteoma
     •   Adipose tissue: lipoma
     •   Smooth muscle: leiomyoma
     •   Skeletal muscle: rhabdomyoma
     •   Blood vessels: hemangioma
     •   Epithelial: adenoma (cystadenoma, papilloma)
                  Nomenclature
• Malignant tumors
  – Mesenchymal: sarcoma
     •   Fibrous: fibrosarcoma
     •   Cartilage: chondrosarcoma
     •   Bone: osteosarcoma
     •   Adipose: liposarcoma
     •   Smooth muscle: leiomyosarcoma
     •   Skeletal muscle: rhabdomyosarcoma
     •   Blood vessels: angiosarcoma
  – Epithelial: carcinoma
     • Gland forming: adenocarcinoma
     • Squamous: Squamous cell carcinoma
     • Transitional cell: Transitional cell carcinoma (urothelial
       carcinoma)
             Nomenclature
• Mixed tumors:
  – Pleomorphic adenoma of salivary gland
  – Fibroadenoma of breast
• Teratoma: more than one germ-cell layer
  – Teratoma contains: bone, epithelium, muscle,
    fat, nerve….
                Nomenclature
• Exceptions:
   – Malignant tumors
      • Lymphoma, melanoma, mesothelioma, seminoma


• Hamartoma: not neoplastic, it is rather a
  malformation. Hamartoma contain mixture of
  mature (adult-type) tissue in abnormal distribution
  and arrangement
• Choristoma: Hetrotopic rest. It is normal tissue in
  abnormal place.
         Benign and Malignant
• How do we know benign from malignant
  tumor?
• Features:
  –   Differentiation and Anaplasia
  –   Rate of Growth
  –   Local Invasion
  –   Metastasis
   Differentiation and Anaplasia
• Differentiation is the extent to which tumor cells
  resemble their normal cells morphologically and
  functionally
• Generally:
   – Benign tumors are well differntiated
   – Malignant tumors can be well differentiated,
     moderately differentiated or poorly differentiated. They
     can be “undifferentiated”
• Anaplasia is lack of differentiation
   Differentiation and Anaplasia
• Anaplasia is lack of differentiation
  –   Peomorphism
  –   Hyperchromatic nuclei
  –   High nuclear to cytoplsmic ratio (N/C ratio)
  –   Giant cells
  –   Mitosis
  –   Loss of polarity and normal arrangement
  –   Loss of sturcture
  Differentiation and Anaplasia
• Function:
  – Benign tumors: have normal function eg.
    Adrenal cortical adenoma
  – Malignant tumors: have variable function
    according to the degree of differentiation eg.
    Hepatocellular carcinoma produces bile
  Differentiation and Anaplasia
• Dysplasia:
  – Not neoplstic growth
  – Disordered growth and differentiation
  – Show mild anaplastic features eg. Nuclear
    pleomophism, hyperchromasia, mitosis….
            Rate of Growth
• Benign: slow growing
• Malignant: fast growing
• Relation between Growth and
  Differentiation
             Local Invasion
• Benign tumors: localized, may be
  surrounded by pseudocapsule “capsule”
• Malignant: invasive, infiltrating, destructiv,
  penetrating
                Metastasis
• Secondary implants discontinuous from the
  primary tumor
  – 30% of newly diagnosed cancer has metastasis
  – 20% has occult metastasis
• Modes of metastasis:
  – 1. Seeding in body cavity
  – 2. Lymphtics: lymph nodes
  – 3. Hematogenous: liver, lung, brain….
         Benign and Malignant
• In summary, Features of malignancy are
  –   Less Differentiation and More Anaplasia
  –   Rate of Growth - high
  –   Local Invasion
  –   Metastasis