Dermatologic Surgery, Lasers, and Procedural Dermatology
Technique follows tissue
Procedural questions test whether you can choose the right modality for the lesion and the right technique for the location, while anticipating complications.
Concepts to master
- Biopsy techniques: punch for deep inflammatory or tumoral lesions; shave for exophytic lesions; excisional for suspected melanoma. Choose the site that is most diagnostic, not the most convenient.
- Excision and closure: respect relaxed skin tension lines, undermine for tension-free closure, and know when to use second-intention healing or grafts.
- Mohs micrographic surgery: indicated for tumors in cosmetically or functionally sensitive areas, recurrent tumors, and ill-defined borders.
- Lasers: vascular lasers (pulsed dye) for port-wine stains and telangiectasia; pigment lasers (Q-switched) for lentigines and tattoos; fractional resurfacing for scars and photoaging; hair removal with appropriate wavelength for skin type.
- Complications: hypertrophic scarring, pigmentary alteration, infection, and recurrence. Darker skin types are at higher risk of postinflammatory hyperpigmentation after resurfacing.
Traps
The commonest trap is choosing a destructive modality (cryotherapy, electrodesiccation) for a lesion that has not been histologically confirmed - never destroy a possible melanoma. Another is ignoring anatomic danger zones (temporal region, nasolabial fold) where nerves and vessels are at risk. Also remember that laser settings must be adjusted for skin type to avoid burns and dyspigmentation.
Rule of thumb
If the diagnosis is uncertain, biopsy before you destroy. If the diagnosis is malignant and the location is sensitive, consider Mohs. If the patient has darker skin, counsel on pigmentary risk before any resurfacing procedure.