Clinical meaning
Skin biopsy provides tissue for histopathological diagnosis of dermatologic conditions. The choice of biopsy technique depends on the suspected diagnosis and lesion characteristics. The epidermis (0.05-1.5 mm thick) contains keratinocytes, melanocytes, and Langerhans cells. The dermis (1-4 mm thick) contains collagen, elastin, blood vessels, nerves, and adnexal structures. A shave biopsy samples the epidermis and superficial dermis, appropriate for superficial lesions where depth of invasion is not critical. A punch biopsy (2-8 mm circular blade) obtains a full-thickness cylinder through epidermis, dermis, and into subcutaneous fat, ideal for inflammatory dermatoses, vesiculobullous diseases, and panniculitis. Excisional biopsy removes the entire lesion with margins, used when melanoma is suspected (preserving Breslow depth) or for complete removal of a concerning lesion.
Diagnosis & workup
Diagnostics & workup: - Select biopsy technique based on clinical differential: shave for epidermal lesions, punch for dermal/inflammatory processes, excisional for suspected melanoma - Choose biopsy site: most representative lesion, include border of normal and abnormal skin for inflammatory conditions - Order appropriate pathology: H&E stain for routine, direct immunofluorescence for autoimmune bullous diseases, special stains for infections - Document lesion characteristics (size, color, morphology) and anatomic location - Photograph lesion before biopsy when possible - Order wound culture separately if infection suspected