Introduction to Neoplasia

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Introduction to Neoplasia

• Major Topics for Discussion
• Definition of neoplasia
• Benign neoplasms
• Malignant neoplasms
• Spread of neoplastic cells (metastasis)
• Clinical evaluation grading and staging
• Epidemiology
• Oncogenes and tumor suppressor genes

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Neoplasia

• Clonal proliferation of cells
• Autonomous growth - uncoordinated
• Derived from cells with proliferative capacity
  (active cell cycle)
• Results from alterations in DNA
• Some resemblance to cell of origin

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Classification

• Benign
• vs
• Malignant

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Benign Neoplasms

• Grow slowly
• Do not invade adjacent tissues or metastasize
  (spread to distant sites)
• Often are encapsulated
• Closely resemble cell of origin (differentiated)
• Uncommonly cause patient death

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Uterine Leiomyoma (benign smooth muscle cell
tumor)
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Benign Gastrointestinal Polyp
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Benign Brain Tumor (Meningioma)
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Malignant Neoplasms

• Grow more rapidly
• Invade adjacent tissues and have potential to
  metastasize
• Not encapsulated
• Less-closely resemble cell of origin
• More-likely to cause patient death

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Adenocarcinoma of Colon
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Adenocarcinoma of Uterus
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Squamous Cell Carcinoma
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Nomenclature

• General rules
• cell type oma benign neoplasm
• cell type carcinoma
• malignant neoplasm of epithelial origin
• cell type sarcoma
• malignant neoplasm of mesenchymal origin

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Examples (Benign Malignant)

• Chondroma condrosarcoma
• Lipoma liposarcoma
• Adenoma adenocarcinoma (of breast)
• Papilloma squamous cell carcinoma

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Exceptions to Rules

• Malignant tumors include
• Teratoma
• Seminoma
• Lymphoma
• Melanoma

These neoplasms have an oma suffix, but they
are malignant.
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Morphology of Neoplasms

• Differentiation degree of resemblance to normal
  cell of origin
• Anaplasia lack of differentiation
• Pleomorphism variation in cell size and nuclear
  appearance
• Mitotic rate reflects proliferative rate
• Necrosis outgrow blood supply

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Gross Microscopic Features
Benign Meningioma
Malignant Melanoma
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Normal Cartilage
Benign Neoplasm of cartilage
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Malignant Chondrosacrcoma
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Squamous Cell Carcinoma(note the keratin
pearls)
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Spread of Neoplasms

• Carcinoma in situ
• (no invasion of the basement membrane)
• Local invasion
• Seeding of body cavities (carcinomatosis)
• Distant metastasis
• Lymphatic spread
• Hematogenous spread

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cervical biopsy shows carcinoma in-situ - CIS
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Invasive Cervical Squamous Cell Carcinoma
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Malignant Melanoma (radial growth phase)
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Bone Metastases of Malignant Melanoma
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Metastatic Liver Cancer
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Peritoneal Carcinomatosis - Widely Disseminated
Cancer
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Hematogenous Spread
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Lymphatic Spread
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Mechanisms of Metastatis

• Altered Cell Adhesion
• Altered Cell Motility
• Hydrolytic enzymes
• Invasion

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Grading and Staging

• Used to predict the behavior of neoplasms
  (prognosis) and determine appropriate therapy
• Grading assessment of degree of differentiation
  and proliferative capacity
• Staging assessment of tumor size and extent of
  spread locally and distantly

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Epidemiology

• 20 of total mortality in the US
• Epithelial cancers (lung, colon, breast,
  prostate) are most common in adults
• Leukemia, lymphoma, CNS neoplasms are most common
  in children
• Geographic differences in incidence
• Environmental associations (carcinogens)

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Cancer Incidence in US Males
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Cancer Incidence US Females
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Neoplasia is a Genetic Disease

• Oncogenes
• Tumor suppressor genes

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Chromosomal Translocation and Neoplasia
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Retinoblastoma and Rb Tumor Suppressor Gene
Mutations
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Path Key Words

• Adenocarcinoma
• Adenoma
• Carcinoma in situ
• Chondroma
• Chondrosarcoma
• Grading
• Hepatoma
• Leukemia
• Lipoma

• Melanoma
• Metastasis
• Peritoneal carcinomatosis
• Squamous cell carcinoma
• Staging
• Teratoma
• Transitional cell carcinoma