Cryotherapy — SCE Dermatology MCQ
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Correct answer: B — Intracellular ice crystal formation causing cell membrane disruption and vascular stasis
The best answer is “Intracellular ice crystal formation causing cell membrane disruption and vascular stasis”. Rapid growth, induration, tenderness, ulceration or other suspicious evolution in a keratotic lesion should prompt assessment for invasive squamous malignancy rather than reliance on a single population risk estimate. The alternatives “Radiation damage, after clinicopathological correlation, after specialist assessment, when the full phenotype supports it”, “Chemical burn, after specialist assessment, when the full phenotype supports it”, “Osmotic lysis, when the full phenotype supports it, within an appropriate UK pathway”, “Thermal denaturation of proteins, within an appropriate UK pathway” are clinically adjacent possibilities, but they do not fit the defining morphology, distribution, histopathology, risk signal or management sequence in this stem.
Reference: NICE NG12 suspected skin cancer recommendations: https://www.nice.org.uk/guidance/ng12/chapter/Recommendations-organised-by-site-of-cancer#skin-cancers