Pathology · single question
A 23-year-old male presents with a white edematous lesion on the left buccal mucosa that disappears when stretched. A 17-year-old female presents with large white patches bilaterally on the buccal mucosa that are thickened, velvety, and do NOT disappear when the cheek is stretched. The second patient's diagnosis is most likely:
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Correct answer: A. White sponge nevus
The key differentiator between leukoedema and white sponge nevus is the stretch test. Leukoedema DISAPPEARS when the mucosa is stretched. White sponge nevus persists when stretched. White sponge nevus is a hereditary condition causing thick, velvety white plaques bilaterally on the buccal mucosa that do NOT resolve on stretching. It is benign and requires no treatment.
- A. CORRECT. White sponge nevus is a hereditary (autosomal dominant) mutation in keratin 4 or 13 causing thick, velvety, folded white plaques bilaterally on buccal mucosa. Critically, they do NOT disappear on stretching (unlike leukoedema). It is benign and no treatment is needed.
- B. INCORRECT. Linea alba is a thin white horizontal line on the buccal mucosa at the occlusal plane — not velvety patches.
- C. INCORRECT. Measles causes Koplik spots (tiny white spots on buccal mucosa opposite the molars), not large velvety bilateral patches.
- D. INCORRECT. Leukoedema appears as a grayish-white film on the buccal mucosa that DISAPPEARS when the tissue is stretched — the first patient (23M) has leukoedema.