Skin Biopsy: Diagnostic Role vs. Therapeutic Misconception

A skin biopsy is a diagnostic procedure—not a treatment.

What It Does

• Provides histopathologic diagnosis (inflammatory, neoplastic, infectious, autoimmune)
• Guides definitive therapy (topical, systemic, surgical)
• Establishes prognosis (e.g., melanoma depth, lymphoma subtype)

What It Does Not Do

• Does not cure the condition (except incidentally if entire lesion excised)
• Does not replace clinical judgment—correlation required
• Does not prevent recurrence

Biopsy Types

• Shave (tangential) — epidermal/superficial dermal
• Punch (2–8 mm) — full thickness, small
• Excisional — entire lesion + margins (diagnostic + therapeutic)
• Incisional — portion of large lesion
• Saucerization — deep shave for suspected melanoma

Clinical Pearl

"Biopsy to diagnose, excise to cure." A punch biopsy of a suspected melanoma confirms diagnosis; definitive wide excision follows. Biopsy of a rash guides systemic therapy.

Patients sometimes expect biopsy to "fix" the problem—clear communication manages expectations.