• Cancers - malignant (technically epithelium-derived) 
• Neoplasms - any "new growth"; either malignant of benign

• growth unrelated to host organism
• atypic (structural/functional abnormality)
• autonomous (indep. of growth controls)
• aggressive (displace and invade host tissue)

Note that there is not satisfactory definition for neoplasm.

Hyperplasia

Metaplasia

Dysplasia

• Hyperplasia - ↑ cell numbers
• Metaplasia - change of differentiated tissue to another
• Dysplasia - disorderly development/differentiation; commonalities w/ malignant growth

*All of these increase the likelihood of developing neoplasia

*All of these are reversible processes

*All of these are benign, non-neoplastic processes

1. Hamartoma - mass of cells native to tissue, but lack proper organization
2. Choristoma - mass of cells foreign to tissue
3. Granuloma - a mass of immune cells unable to eliminate a pathogen

1. large lung hamartoma (bronchial cartilage nodule in lung)
2. von Mayenburg complex (bile duct hamartoma in liver)

Hamartomas and choristomas are neoplasms.

T/F

Malignant tumors have metastatic potential. Benign tumors do not.

Metastatis is the secondary growth of a tumor at a site separate from the primary growth

• -oma suffix = benign tumor. (Granuloma is a notable exception)
• carcinomas = malignant epthelial tumors
• sarcomas = malignant mesenchymal tumors
• -blastoma = neoplasms from pluripotent cells
  • contain mixtures of epithelial and mesenchymal elements

Encapsulated (thus, usually benign) tumors that resemble normal derivatives of all three germ layers

Growths resemble normal tissue of organs (brain, hepatice, etc.)

E.g., ovarian teratoma with teeth, hair, etc.

Malignant plasma cell tumor

• these produce antibodies (duh)
• reside in bone marrow
• S&S: CRAB
  • hypercalcemia
  • renal failure
  • anemia
  • bone pain

Epithelial tumors arising from glands

adenomatous polyp - a polyp w/ glandular elements

Finger-like projection from an epithelial surface. Benign or malignant

• pedunculated - long stalk
• sessile - no or short stalk
• papilloma - multiple projections
• adenomatous - with glandular elements

Stalks contain mesenchyme and CT that supports the apical cells of the polyp

Lack of differentiation due to oncogenesis of pluripotent stem cells in a tissue.

Features:

• pleomorphism: fewer cilia, secretory elements in a tumor for a specific tissue
• unduly large nuclei
• multinucleated cells
• cell size discrepancy
• frequent mitosis

*Benign tumors are "more differentiated" than malignant ones

In general, malignant tumors grow fast than benign ones (duh)

Features

• basophilia (RNA and protein abundance)
• larger nuclei
• more nuclei
• ↑ glycogen content
  
  • indication of anaerobic glycolysis
  • Dx = PAS stain

Not corresponding to the normal type

*parallels degree of malignancy

• abberant size/shape
• multiple/larger nuclei
• ↑ mitoses
• abnormal secretion
• crystalloids
• IC lumina
• ↑ microvilli

Anaplasia is an definitive indication of a malignant tumor. Atypia is not.

Anaplasia is context-independent (a single cell can be said to be anaplastic), whereas atypia is context dependent.

Neoplastic cells in culture.

Features:

• Immortality - divide forever
• Anchorage independent - grow in fluid medium
• No contact inhibition - cells grow on top of each other
• Independent of exogenous GF's
• Metastasize in immunodeficient subjects

(This is not benign/malignant-specific)

These features are due to genetic changes within tumor cells.

• motility (ameboid motion)
• abnormal secretions (e.g., metalloproteases degraded BM)
• ↓ adhesion btwn cells
• ↓ IC communication
• changes in cell-surface carbs

1. Neoplastic parenchyma
   • the actual dividing tumor
2. Non-neoplastic stroma
   • the supporting vessels, CT, and cells from the host
   • can be induced and manipulated by the parenchyma
   • lots of CT = scirrhous

Tumors can induce angiogenesis. This is essential for tumor survival.

Capsules encapsulate benign

Pseudocapsules encapsulate malignant

• benign tumors w/o a capsule
  • uterine meiolyomas
  • dermal/hepatic hemangiomas
• pseudocapsules
  • are leaky
  • usually composed of atrophic, dead host tissue