69. Classification of neoplasms. Morphology and biology of tumor growth. Precanceroses. Paraneoplastic syndromes. Clinical classification of malignant tumors. TNM - system. Basic apparatus and instrumental methods. Morphological diagnostics. Tumor markers.

NEOPLASMS

Written by Rhiana Devadasan

Neo = new.

Plasm = cells/tissues.

Neoplasm = abnormal, uncontrolled, uncoordinated, autonomous, excessive, purposeless growth/proliferation of neoplastic cells that persists to form a lump or bump (tumor), which may be benign (non-cancerous) or malignant (cancerous).

(NB: Neoplasia = the process)

Synonyms:

• > Neoplasm
• > Tumor

cancerous versions

• > Cancer
• > Malignancy

Characteristics of Tumor Cells/Neoplasms:

• Uncontrolled growth / Limitless replicative potential (beyond normal hyperplasia)
• Autonomous (i.e. Independent from regulatory mechanisms: e.g. inhibitory GFs, hormones, etc. But NB: DOES need BV. & nn.)
• Self-sufficiency in growth signals
• Sustained angiogenesis
• Anaplasia (poor cell differentiation/↑variability)
• Immortal (i.e. defective apoptosis)
• Loss of cell-to-cell inhibition
• Insensitivity to growth-inhibitory signals
• Defects in DNA repair
• Aggresive (able to invade & infiltrate surrounding tissue)
• Ability to metastasize (beyond site of origin - via lymph/blood vessels)
• Highly adaptive (plasticity)

Morphology & Biology of Tumors

Tumors consist of:

1. Parenchyma - functional tumor cells
2. Stroma - CT, blood vessels, nerves & ECM

Medullary Tumors = tumors containing predominantly parenchymal cells.

Cirrhotic/Desmoplasia Tumors = tumors with excessive CT stroma (tumor is firm).