Page 262 - First Aid for the USMLE Step 1 2020, Thirtieth edition [MedicalBooksVN.com]_Neat

218 SECtIoN II Pathology ` PATHOLOGY—InfLAMMATIOn Pathology ` PATHOLOGY—neOPLASIA

Scar formation Occurs when repair cannot be accomplished by cell regeneration alone. Nonregenerated cells (2°
to severe acute or chronic injury) are replaced by connective tissue. 70–80% of tensile strength
regained at 3 months; little tensile strength regained thereafter. Associated with excess TGF-β.
SCAr TYPe Hypertrophic A Keloid B
COLLAGen SYnTHeSIS  (type III collagen)  (types I and III collagen)
COLLAGen OrGAnIZATIOn Parallel Disorganized
eXTenT Of SCAr Confined to borders of original wound Extends beyond borders of original wound with
“claw-like” projections typically on earlobes,
face, upper extremities

reCurrenCe Infrequent Frequent
PreDISPOSITIOn None  incidence in ethnic groups with darker skin
A B

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