Neoplasia

• Neoplasia


  New growth, defined as "Abnormal mass of tissues the growth of which exceeds and is uncoordinated with that of the normal tissue & persists in the same excessive manner after cessation of the stimuli which evoked the change"
• Topics to be covered

  • Nomenclature and Classification of Neoplasia
  • Characteristics of tumors
  • Pathologic diagnosis of cancer, Grading and staging of tumor
  • Practical points (Vertical integration)
• Tumor-like conditions


  • hemorrhage
  • cyst
  • aneurysm
  • mass
  • lump
  • swelling
  • neoplasia
• Tumor


  Neoplasia, tumor cells have a defect in their DNA which results in a change in structure and function
• Tumor


  • Heritable genetic alterations that are passed down to the progeny of tumor cells
  • Excessive & unregulated proliferation that becomes autonomous (independent of physiologic growth stimuli)
  • Remain dependant on the host for their nutrition and blood supply
• Fundamental to the origin of all neoplasms

  Loss of responsiveness to normal growth controls
• Oncology


  Study of tumors
• Components of all tumors

  • Proliferating neoplastic cells that constitute their parenchyma
  • Supportive stroma made up of connective tissue & blood vessels
• Factors used to name neoplasms

  • Histologic types: mesenchymal and epithelial
  • Behavioral patterns: benign and malignant neoplasms
• Benign tumor


  Reproduces in defiance of the normal restraints
• Malignant tumor


  Reproduces in defiance of the normal restraints and invades and colonizes territories reserved for other cells
• Benign tumors of mesenchymal cells

  • Fibroma
  • Lipoma
  • Chondroma
  • Osteoma
• Malignant tumors of mesenchymal tissue

  • Fibrosarcoma
  • Liposarcoma
  • Chondrosarcoma
  • Osteosarcoma
• Benign tumors of endothelial and related tissues

  • Hemangioma
  • Lymphangioma
• Malignant tumors of endothelial and related tissues

  • Angiosarcoma
  • Lymphangiosarcoma
  • Synovial sarcoma
• Benign tumors of muscle

  • Leiomyoma
  • Rhabdomyoma
• Malignant tumors of muscle

  • Leiomyosarcoma
  • Rhabdomyosarcoma
• Adenoma


  Benign epithelial neoplasm that forms a glandular pattern
• Papillomas

  Benign neoplasms producing microscopically or macroscopically visible finger-like or warty projections from epithelial surface
• Cystadenoma


  Benign epithelial tumors that form large cystic masses
• Papillary cystadenoma


  Tumors that produce papillary patterns that protrude into cystic spaces
• Polyp


  Tumor that produces macroscopically visible projection above a mucosal surface
• Carcinomas


  Malignant neoplasms of epithelial cell origin
• Types of carcinomas


  • Squamous cell carcinoma
  • Adenocarcinoma
• Principles of classification


  • Epithelial origin: Benign - +oma, Malignant - Carcinoma
  • Connective tissue origin: Benign - +oma, Malignant - Sarcoma
• Teratomas


  Made up of a variety of parenchymal cell types representative of more than one germ layer, arise from totipotent cells, mostly found in gonads
• Choristoma


  Ectopic rest of normal tissue
• Hamartoma


  Mass of disorganized but mature specialized cells or tissue indigenous to the particular site
• Lymphomas


  Malignancies of lymphoid tissue
• Leukemias


  Malignant neoplasms of blood forming cells
• Lung chondroid hamartoma


  • Disorganized proliferation of various connective & epithelial tissues normally found in the lung, including cartilage and glands
• Pancreatic heterotopia

  • In the small intestine and gallbladder
• Characteristics of benign and malignant neoplasms

  • Differentiation and anaplasia
  • Rate of growth
  • Local invasion
  • Metastasis
• Differentiation


  Extent to which tumor parenchymal cells resemble comparable normal cells both morphologically and functionally
• Anaplasia


  Malignant neoplasms composed of undifferentiated cells, literally means to form backward
• Morphologic changes marking anaplasia

  • Pleomorphism
  • Abnormal nuclear morphology
  • High nuclear cytoplasmic ratio
  • Large nucleoli
  • High number and often abnormal mitoses
  • Tumor giant cells
  • Necrosis
• Rate of growth


  Most benign tumors grow slowly, most malignant tumors grow rapidly sometimes at an erratic pace
• Growth rate of neoplasms correlates with their level of differentiation, most malignant neoplasms grow more rapidly than benign neoplasms
• Local invasion


  Benign neoplasms remain localized to their site of origin and do not infiltrate, invade or metastasize, malignant neoplasms progressively infiltrate and invade surrounding tissue
• Benign neoplasms usually develop a fibrous capsule that contains them as a discrete, palpable and easily movable mass