keloid (hypertrophic scar)

Introduction

Nodular, firm, movable, non-encapsulated hypertrophic scar tissue. It is tender & frequently painful.

Etiology

• unknown
• generally follows injury to skin
  • surgical incision
  • lacerations
  • burns
  • inflammatory skin conditions

Epidemiology

• age: childhood through senescent
• equal incidence in males & females
• more common in blacks than whites

Pathology

• whorls of young fibrous tissue & fibroblasts in haphazard arrangement
• thick eosinophilic, irregularly distributed bands of collagen (keloid)
• occurs in the dermis & adjacent subcutaneous tissues

* histopathology images

Clinical manifestations

• papules, nodules, tumors, large tuberous lesions
• generally tender & frequently painful, but may be asymptomatic
• cosmetically disfiguring
• color; red, tan, brown, flesh-colored
• may be claw-like extensions beyond original site of injury (keloids)
• hypertrophic scars tend to regress, keloids may continue to increased in size for decades

* images

Differential diagnosis

• scar
• dermatofibroma
• dermatofibrosarcoma
• desmoid tumor
• foreign body granuloma
• sarcoidosis

Management

• prevention
  • avoid skin trauma
  • triamcinolone acetonide (5 mg/mL) injected at the incision site
• crytotherapy with liquid nitrogen
• intralesional triamcinolone acetonide 10-40 mg/mL q month (lesions may be difficult to inject because of collagen)
• combinations of cryotherapy & intralesional triamcinolone
• surgical excision:
  • lesions often recur larger than the original lesion
    • surgical resection with immediate infiltration of glucocorticoids without recurrence in case report
  • post-surgical irradiation with iridium has been reported to be of benefit

More general terms

• abnormal morphologic structure (malformation)