Skin Biopsy — SCE Dermatology MCQ

Instant feedback + full explanation. One question, done properly.

EasyDermatological SurgerySkin BiopsySCE Dermatology

A dermatologist is performing a punch biopsy. She selects a 4 mm punch. For most dermatological conditions, what is the minimum recommended punch biopsy diameter to ensure adequate tissue for histological assessment?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: B — 3-4 mm

The correct answer is B, 3-4 mm. This size range provides a full-thickness core through epidermis, dermis and into subcutaneous fat, which is the minimum needed to give a dermatopathologist an adequate architectural sample for most inflammatory, infective and neoplastic skin conditions, including orientation for direct immunofluorescence when required. UK NHS dermatology practice reflects this standard, with departmental guidance describing punch biopsies as removing a core of tissue of this size for routine histological work-up. Larger punches (5-6 mm or more) are reserved for panniculitis, deep morphoea or when a larger area of subcutis is needed, while smaller diameters compromise the ability to assess the full dermal architecture and adnexal structures reliably.

Reference: https://www.nice.org.uk/guidance/conditions-and-diseases/skin-conditions