Neoplasia Notes

Germinal Layers

  • Ectoderm: outer layer (epidermal cells of skin, neurons of brain, pigment cell)
  • Mesoderm: middle layer (notochord, bone tissue, tubule cell of the kidney, red blood cells, facial muscle)
  • Endoderm: internal layer (stomach cell, thyroid cell, lung cell)
  • Germ cells: sperm, egg

Carcinomas

  • Malignant neoplasms from ectoderm or endoderm.
  • Examples: squamous cell carcinoma of cervix, adenocarcinoma of stomach, hepatocellular carcinoma, renal cell carcinoma

Sarcomas

  • Malignancies from mesoderm (connective tissues).
  • Examples: leiomyosarcoma, chondrosarcoma, osteosarcoma, liposarcoma

Mixed Tumors

  • Neoplasia with more than one cell type from one germ layer.
  • Example: benign mixed tumor (pleomorphic adenoma) of salivary gland

Teratomas

  • Neoplasia with more than one cell type from more than one germ layer.
  • Common in the ovary.

-Blastoma Tumors

  • Resemble primitive embryonic tissues; often pediatric neoplasms.
  • Examples: retinoblastoma, neuroblastoma, hepatoblastoma, medulloblastoma

Malignant Neoplasms Without Benign Counterparts

  • Hematopoietic and lymphoid cells: leukemias and lymphomas
  • Gliomas (astrocytomas, oligodendrogliomas, glioblastoma): glial cells in the CNS

Carcinomas Origin

  • Arise from epithelial surfaces (GI, respiratory, urogenital, biliary tracts, skin) and organs with epithelial-lined ducts (breast, pancreas, salivary gland, liver).
  • Can arise from endocrine glands (testis, ovary).
  • Composed of polygonal-shaped cells.
  • Adenocarcinomas: form glandular configurations.
  • Squamous cell carcinomas: form solid nests of cells with distinct borders and pink keratinized cytoplasm.

Sarcomas Origin

  • Arise from soft tissues (connective tissues, muscle, vessels, organ coverings).
  • Composed of pleomorphic spindle-shaped cells.

Tumors of Epithelial Origin

  • Stratified squamous: Squamous cell papilloma, Squamous cell carcinoma
  • Basal cells of skin: Basal cell carcinoma
  • Epithelial lining of glands: Adenoma, Adenocarcinoma
  • Urinary tract epithelium: Papilloma, Papillary carcinoma, Transitional-cell papilloma, Transitional-cell carcinoma

Tumors of Mesenchymal Origin

  • Connective tissue: Fibroma, Fibrosarcoma, Lipoma, Liposarcoma, Chondroma, Chondrosarcoma, Osteoma, Osteogenic sarcoma
  • Vessels/Coverings: Hemangioma, Angiosarcoma, Meningioma, Invasive meningioma, Neurofibroma/Neurilemmoma, Malignant peripheral nerve sheath tumor
  • Blood cells: Leukemia, Lymphoma
  • Muscle: Leiomyoma, Leiomyosarcoma, Rhabdomyoma, Rhabdomyosarcoma

Carcinoma vs. Sarcoma

  • Carcinoma: malignant tumor of epithelial origin.
    • More common.
    • Older age.
    • Slower growth.
    • Lymphatic spread.
    • From colon, breast, lung, prostate.
  • Sarcoma: malignant tumor of mesenchymal origin.
    • Less common.
    • Any age.
    • Rapid growth.
    • Hematogenous spread.
    • From musculoskeletal system.

Examples

  • Breast: Invasive Ductal Carcinoma (poorly circumscribed, firm, infiltrative)
  • Breast: Fibroadenoma (well-circumscribed, encapsulated, rubbery)
  • Colon: Adenocarcinoma, Adenoma
  • Condyloma acuminata: Koilocyte raisin-like nuclei with halo (Koilocytosis)
  • Invasive squamous cell carcinoma: Well differentiated/Poorly differentiated
  • Uterine: Leiomyoma/Leiomyosarcoma
  • Ovarian: Cystadenoma (benign), High-grade serous carcinoma
  • Pleomorphic adenoma of parotid: Ductal/Myoepithelial
  • Ovarian mature teratoma