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