General Pathology

Question 1

Tumor grade vs. stage; which is better indicator for prognosis?

Answer 1

Grade: Degree of cellular differentiation and mitotic
activity on histo.

Stage: Degree of localization/spread based on site and size of 1° lesion, spread to LNs, presence of mets (TNM)

Stage generally has more prognostic value than
grade (eg, a high-stage yet low-grade tumor is
usually worse than a low-stage yet high-grade
tumor). Stage determines Survival.

Question 2

Labile, stable and permanent tissues

Answer 2

• labile: constant regeneration, contain stem cells (skin: stem cells in basal layer; GIT: stem cells in mucosal crypts; BM: hematopoietic CD34+ stem cells; type II pneumocytes lung)
• stable: quiescent but can re-enter cell cycle when needed to regenerate tissue. e.g. liver, PCT of kidney (ATN: regenerates over time)
• permanent: lacks significant regenerative potential (will form a scar instead). myocardium, skeletal muscle, neurons.

Question 3

Components of granulation tissue, and process of scar formation

Answer 3

Granulation tissue contains: capillaries (provide nutrients), myofibroblasts (contract down the wound), fibroblasts (deposite type III collagen). To make a scar, Type III collagen –> Type I collagen by collagenase using Zn cofactor

Question 4

Deficiencies that delay wound healing

Answer 4

• Vit C (scurvy): cannot hydroxylate pro and lys procollagen residues –> later can’t cross-link collagen (strengthening)
• Copper: cofactor for lysyl oxidase which cross-links lys and hydroxylysine to form stable collagen
• Zinc: cofactor for collagenase (TIII –> TI collagen)

Question 5

Hypertrophic scar vs. keloid

Answer 5

• Hypertrophic scar: excess production of TI collagen, localized to the wound
• Keloid: excess TIII collagen, out of proportion to the wound, commonly in AA pts and on earlobes