Question
A 36-year-old male comes for minor skin surgery to remove a benign lesion. The clinician wants to counsel him about abnormal scar formation. Which anatomical region has the highest tendency to develop exaggerated scar tissue growth beyond wound margins?
a) Lower lumbar area
b) Central chest region
c) Abdominal wall
d) Inner (flexor) aspect of forearm
e) Hair-bearing scalp
Answer
b) Central chest region
Detailed Explanation
Keloid scars are characterized by excessive collagen deposition leading to a scar that extends beyond the original wound boundaries, unlike hypertrophic scars which remain confined.
Why the central chest (sternum) is most prone:
- High skin tension area → mechanical forces stimulate fibroblast activity
- Increased collagen synthesis and reduced degradation
- Frequent exposure to trauma/stretching (movement of chest wall)
Other commonly affected areas (descending order):
- Sternum (most common)
- Shoulders and upper arms
- Earlobes (piercings)
- Neck and jawline
- Extensor surfaces
Areas less prone:
- Flexor surfaces
- Abdomen (moderate risk only post-surgery)
- Scalp (rare due to different follicular biology and less tension)
Risk factors:
- Darker skin types
- Young adults
- Genetic predisposition
Key pathological concept:
Keloids behave like benign fibroproliferative tumors, often recurring after excision
Cheat Sheet for Exam
Keloid Scar – High-Yield Points
- Extends beyond wound margins
- Does not regress spontaneously
- High recurrence after excision
- Caused by excess collagen (Type III > Type I initially)
Common Sites (VERY IMPORTANT ORDER)
- Sternum
- Shoulder
- Neck
- Face
- Extensor limbs
Risk Factors
- Dark skin
- Age < 30–40 years
- High skin tension areas
Treatment
- First-line: Intralesional steroids (triamcinolone)
- Others: silicone sheets, pressure therapy, laser
- Surgery → risk of worsening
Flash Cards
Q1. What is the defining feature of a keloid scar?
A: Extends beyond original wound margins
Q2. Most common site of keloid formation?
A: Sternum
Q3. Which population is at higher risk?
A: Individuals with darker skin
Q4. First-line treatment for early keloid?
A: Intralesional corticosteroids
Q5. Why is surgery risky in keloids?
A: High recurrence and may worsen lesion
MCQs (High Difficulty)
MCQ 1
A 28-year-old woman develops a raised scar after ear piercing that continues to enlarge beyond the wound margins. Which mechanism best explains this condition?
a) Reduced fibroblast activity
b) Excess collagen synthesis with reduced breakdown
c) Autoimmune vasculitis
d) Impaired keratinocyte proliferation
Answer: b
Explanation: Keloids result from excessive fibroblast activity and collagen deposition exceeding degradation.
MCQ 2
Which of the following sites is LEAST likely to develop a keloid?
a) Shoulder
b) Sternum
c) Flexor surface of wrist
d) Earlobe
Answer: c
Explanation: Flexor surfaces have lower tension → reduced risk.
MCQ 3
Which statement about keloid scars is FALSE?
a) They extend beyond original wound
b) They may regress spontaneously over time
c) They are more common in young adults
d) They recur after excision
Answer: b
Explanation: Keloids do NOT regress spontaneously (hypertrophic scars may).
MCQ 4
A surgeon plans an incision to reduce risk of abnormal scarring. Which principle is most appropriate?
a) Incision perpendicular to skin tension lines
b) Incision along relaxed skin tension lines
c) Deep incision to avoid dermis
d) Use of absorbable sutures only
Answer: b
Explanation: Incisions along relaxed skin tension lines reduce keloid risk.
MCQ 5
A patient with keloid formation is started on treatment. Which is the most appropriate initial therapy?
a) Radiotherapy
b) Surgical excision alone
c) Intralesional triamcinolone
d) Oral antibiotics
Answer: c
Explanation: Steroid injection reduces fibroblast activity and collagen synthesis.
MCQ 6
Which factor most strongly predisposes to keloid formation?
a) Advanced age
b) Low skin tension
c) Dark skin phenotype
d) Vitamin C deficiency
Answer: c
Explanation: Higher incidence in darker skin due to fibroblast activity differences.
Summary for Quick Exam Revision
Keloid scars are fibroproliferative lesions that extend beyond the original wound and do not regress spontaneously, distinguishing them from hypertrophic scars. They occur due to excessive collagen production and reduced degradation, often behaving like benign tumors with a high recurrence rate after excision. The most common site is the sternum, followed by shoulders, neck, and earlobes—areas characterized by high skin tension. Risk factors include younger age and darker skin types. Flexor surfaces and scalp are relatively protected due to lower tension and biological differences. Prevention involves making surgical incisions along relaxed skin tension lines. First-line treatment is intralesional corticosteroids such as triamcinolone, while surgical excision alone is avoided due to recurrence risk. Understanding site predilection and pathophysiology is crucial for both exam success and clinical counseling.