Neoplasia: Benign vs Malignant

Cancer Stats

• Second leading cause of death in USA

• Lung cancer = most common cause of death

List and describe which cancers arrise from each Risk Factors (6)

Risk Factors

• Infections

  • HPV 

    • Cervical, head, neck carcinoma

  • EBV 

    • Lymphoma

  • Hep B/C

    • hepatocellular carcinoma

• Smoking

  • head/neck, pancreas, bladder, lung (90%) cancer

• Alcohol 

  • head/neck hepatocellular carcinoma

• Obesity:

  • Higher rates of death b/c comorbidity

• Env. Carcinogens

  • Lung: Many risks

  • Asbestos: mesothelioma

  • Vinyl chloride: Hepatic angiosarcoma

  • Benzene: AML

• Age:

  • Most carcinoma = age > 55

  • b/c decline in immune surveillance + somatic mutation accumulation

List and describe the predisposing conditions that can lead to cancer

Predisposing conditions

• Chronic Inflammation:

  • Immune production -> O2 radicals -> damage DNA 

  • Cytokines -> cell survival

• Precursor lesions 

  • Hyperplasia exposure to trophic stimulation

    • (endometrial hyperplasia)

• Immunodeficiency 

  • Especially T cell defects 

  • @ risk for oncogenic viruses

• Inheritance 

  • 5-10% of cancers 

Describe the characteristics of Benign tumors

Characteristics:

• close to normal histology

• Usually a mass w/ smooth, defined borders (capsule)

• Usually a low mitotic rate

List and describe the origins of the 4 major malignant tumor types

Major malignant tumor types

• Carcinoma 

  • of epithelial origin 

• Sarcoma

  • mesenchymal origin 

    • (muscle, fibrous tissue, bone) 

• Lymphoma/Leukemia

  • hematopoietic cells 

    • (bone marrow) 

• Melanoma

  • derived from melanocytes

How do you determine if its Benign or Malignant

Determination of Benign vs. Malignant

• Morphology

  • Degree of differentiation

• Rate of growth

  • Mitosis

• Invasion

  • Local

  •  Metastatic

Describe how malignant tumors change their morphology:

• Define Differentiation 

• List and describe the 5 changes that can occur in morphology

Differentiation 

• extent to which neoplastic cells resemble normal cells

---

Type of Change:

• Cytologic changes 

  • Dif cell morphology

• Changes in tissue Architecture

  • Loss of Order

  • Loss of Polarity

• # of Dif Cells

• Change in nuclear morphology

  • Increased nuclear:cytoplasmic

  • Irregular nuclear shape

  • clumped chromatin or darkly stained chromatin (hyperchromatic)

• Pleomorphism

  • variation in cell size and shape

Describe how we know if a tumor is malignant based on their rate of growth

Morphology: Mitosis

• Often increased rate of growth in malignant tumors 

  • (but not always!)

  • Determined by # of mitotic figures

• Presence of atypical or bizarre mitotic figures 

  • (but not always!)

List the proof in tissue architecture that there is a malignant tumor

Morphology: Changes in tissue architecture

Proof:

• Presence of inflammatory response to tumor 

• Presence of stromal response to tumor

  • Localized fibrotic tissue

• Necrosis

  • Tumor outgrows blood supply -> dies

Describe these terms

• Hyperplasia

• Metaplasia

• Dysplasia

• Carcinoma in situ

• Hyperplasia 

  • reactive ordered growth. 

  • ↑  # of cell layers

• Metaplasia 

  • One cell type -> another

  • Due to chronic injury

• Dysplasia 

  • premalignant lesion

  • disordered growth + cytologic changes

• Carcinoma in situ 

  • severe dysplasia involving full thickness of epithelium

  • Not invasive

• Goblet cell hyperplasia (A)

• Basal cell hyperplasia (B)

• Squamous metaplasia (C)

• Squamous dysplasia (D)

• Carcinoma in situ (E)

• Carcinoma invasive (F)

What two things are characteristics of Squamous Cell Carcinoma

• Keratin pearls

• Intercellular bridges

What two things are characteristics of Adenocarcinoma

• Glandular differentiation

• Mucin production

• Normal cartilage (A)

• Benign chondroma (B)

• Chondrosarcoma (C)

  • bizarre shaped nuclei, hyperchromatic nuclei

Follicular lymphoma

---

Characteristics:

• BCL-2 stain germinal centers

• Abnormal architecture: Too many lymphoid follicles

• Loss of polarization

List and describe the 4 type of Tumor Markers

Tumor Markers

• Immunohistochemistry (IHC) 

  • identify specific proteins in tissue sample

• Antibodies bind target antigens on tissue

• Cytokeratin stain (B): carcinoma

• S-100 stain (D): melanoma