What is the difference between hypertrophic scar and keloid
• Both excessive fibrous tissue responses to healing
• Hypertrophic scar is confined to site of original injury, is not progressive beyond 6 months and frequent in children. When a hypertrophic scar is excised it rarey recurs.
• Hypertrophic scar is a result of a problem with injury – eg burn wound, infected wound, skin sutured under tension or across Langer’s lines
• Keloid extends beyond the boundary of original injury, continues to grow even years after injury, rare before puberty and will recur after excision.
• Keloid is result of genetic and racial predisposition (dark skin) in characteristic place (sternum)
What is the management of keloid or hypertrophic scaringg
• Prevention: Incision orientation, avoid tension, avoid infection
• Obseravtion – never excise within first 6 months as spontaneous regression may occur in hypertophic scarring
• Conservative – triamcinolone injection (long-acting synthetic corticosteroid), intra-lesion 5-FU, pulsed dye laser, XRT, pressure
• Surgery – Excision alone, avoiding risk factors from previous surgery and changing orientation of wound (Z plasty). Also combined with post-op conservative measures - excision combined with pre-, post- or intra-operative steroid injection, XRT after excision substantially reduces risk of recurrence.
What is keratoacanthoma
• Low grade malignancy of skin originating in pilosebaceous glands which resembles SCC.
• Once considered benign lesion that resembled malignancy, it is now recognized as an abortive malignant process.
• Grows rapidly over a few weeks and resolves rapidly over a few months leaving a residual scar.
• Central ulceration or keratin plug
What is the treatment
• Surgical excision with margin of 3-5mm.
• Mohs micrographic surgery for recurrent lesions or lesions in cosmetically sensitive areas.
• XRT can be used in large tumours where excison will be difficult or disfiguring.
• Medical treatments are considered for patients where the diagnosis is clear where there are multiple tumours which are inoperable because of location or medical condition of patient.