Nomenclature and Classification of Tumors

Nomenclature and Classification of Tumors

Nomenclature and Classification of Tumors

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Definitions & Tumor Components - Naming Game Intro

  • Neoplasia: "New growth"; abnormal mass of tissue, growth exceeds & is uncoordinated with normal tissues, persisting after cessation of stimuli.

  • Tumor: Originally swelling; now largely synonymous with neoplasm.

  • Oncology: Study of tumors (Greek oncos = tumor).

  • Tumor Components:

    • Parenchyma: Transformed neoplastic cells. Determines tumor's biological behavior & is the basis of classification/naming.
    • Stroma: Supporting, non-neoplastic host-derived framework (connective tissue, blood vessels, inflammatory cells). Essential for tumor growth & support.
  • Basic Classification (Benign vs. Malignant):

    • Benign: Generally localized, slow-growing, well-differentiated; rarely fatal.
    • Malignant (Cancer): Invasive, destructive, capable of metastasis; often fatal.

⭐ Hamartoma: A benign, disorganized mass of mature cells/tissues indigenous to the specific site (e.g., lung hamartoma with cartilage, bronchi). Considered a developmental malformation, not a true neoplasm.

Benign Tumor Nomenclature - Gentle "-oma" Endings

  • General: Suffix "-oma" to cell of origin = usually benign.
    • ⚠️ Exceptions: melanoma, lymphoma, seminoma, hepatoma (all malignant).
  • Epithelial Benign Tumors:
    • Adenoma: Glandular origin/pattern.
      • E.g., thyroid, colonic adenoma; fibroadenoma (breast).
    • Papilloma: Epithelial, finger-like projections.
      • E.g., squamous cell papilloma, intraductal papilloma.
    • Cystadenoma: Adenoma + cysts.
      • E.g., ovarian serous/mucinous cystadenoma.
  • Mesenchymal Benign Tumors:
    • Cell of origin + "-oma".
      • Fibroma (fibrous tissue)
      • Lipoma (adipose tissue)
      • Chondroma (cartilage)
      • Osteoma (bone)
      • Leiomyoma (smooth muscle) 📌 "L" for Leiomyo & Ladies (uterus).
      • Rhabdomyoma (striated muscle)
      • Hemangioma (blood vessels)
      • Lymphangioma (lymph vessels)

⭐ Leiomyoma (fibroid) is the most common benign tumor in women, typically in the uterus. Leiomyoma: Spindle cells, no atypia, low mitosis

Malignant Tumor Nomenclature - Cancer's Code Names

  • General Suffixes:
    • -carcinoma: Malignant tumor of epithelial origin (e.g., adenocarcinoma, squamous cell carcinoma).
    • -sarcoma: Malignant tumor of mesenchymal/connective tissue origin (e.g., fibrosarcoma, osteosarcoma, liposarcoma).
  • Hematologic & Lymphoid Malignancies:
    • Leukemia: Malignancy of hematopoietic cells in blood/bone marrow.
    • Lymphoma: Solid tumor of lymphoid cells (e.g., Hodgkin, Non-Hodgkin).
    • Multiple Myeloma: Malignancy of plasma cells.
  • Key Exceptions & Unique Names (Malignant):
    • Melanoma (melanocytes)
    • Seminoma (testicular germ cells)
    • Hepatoma (term for hepatocellular carcinoma)
    • Mesothelioma (mesothelium)
    • Lymphoma (as above)
    • Leukemia (as above)
    • 📌 Mnemonic: "My Lovely Hot Sister Makes Lasagna" (Melanoma, Lymphoma, Hepatoma, Seminoma, Mesothelioma, Leukemia).
  • Blastomas: Malignant tumors of embryonal/primitive undifferentiated cells (e.g., neuroblastoma, retinoblastoma, nephroblastoma). Common in children.

⭐ Carcinomas generally metastasize via lymphatics first; sarcomas typically spread hematogenously.

Special Tumor Categories - The Unique Crew

  • Mixed Tumors: Show divergent differentiation, often biphasic (epithelial & mesenchymal components).
    • Example: Pleomorphic adenoma (salivary gland) - epithelial cells and myxoid stroma with chondroid/osseous metaplasia.
  • Teratomas: Derived from ≥2 (often 3) germ cell layers; totipotent cells.
    • Originate from gonads (ovary, testis) or midline embryonic rests.
    • Types: Mature (benign, e.g., dermoid cyst), Immature (malignant), Monodermal (specialized, e.g., struma ovarii).

    ⭐ Mature cystic teratomas of the ovary are common and often contain hair, teeth, and sebaceous material.

  • Hamartoma: Disorganized but mature, benign mass of cells indigenous to the involved site.
    • Example: Pulmonary chondroid hamartoma (cartilage, bronchioles).
  • Choristoma (Heterotopia): Congenital anomaly; microscopically normal tissue in an abnormal location.
    • Example: Pancreatic tissue in stomach wall.

Testis Teratoma Gross Pathology

📌 Mnemonic for germ layers in teratoma: Every Monster Eats (Ectoderm, Mesoderm, Endoderm).

High-Yield Points - ⚡ Biggest Takeaways

  • Benign tumors usually end in "-oma" (e.g., Fibroma), but melanoma, lymphoma, seminoma, hepatoma are malignant exceptions.
  • Carcinomas are malignant epithelial tumors; adenocarcinomas arise from glandular epithelium.
  • Sarcomas are malignant mesenchymal tumors (e.g., Liposarcoma).
  • Teratomas derive from totipotent cells (all three germ layers); can be benign or malignant.
  • Hamartoma: disorganized mature native tissue; Choristoma: ectopic architecturally normal tissue.
  • Anaplasia and pleomorphism are hallmarks of malignancy.

Practice Questions: Nomenclature and Classification of Tumors

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Most common benign breast tumour:

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Flashcards: Nomenclature and Classification of Tumors

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Pleomorphic adenoma is a slow growing _____ tumor that is potentially malignant

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Pleomorphic adenoma is a slow growing _____ tumor that is potentially malignant

benign

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