Darier disease (keratosis follicularis) shows characteristic histopathological features. Which of the following is the MOST pathognomonic finding on skin biopsy?
- A Suprabasal acantholysis with 'corps ronds' and 'corps grains' in the stratum spinosum/granulosum ✓
- B Parakeratosis with neutrophilic microabscesses in the stratum corneum
- C Lichenoid inflammation with 'saw-tooth' rete ridges and colloid bodies
- D Subcorneal pustule with acantholytic cells and no neutrophils
Correct answer: A. Suprabasal acantholysis with 'corps ronds' and 'corps grains' in the stratum spinosum/granulosum
Explanation
Darier disease (ATP2A2 mutation, SERCA2 pump defect) shows acantholysis at the suprabasal level with distinctive dyskeratotic cells: 'corps ronds' (rounded cells with pyknotic nucleus surrounded by clear halo in the spinous layer) and 'corps grains' (flattened grain-like parakeratotic cells in the granular layer). These dyskeratotic cells result from abnormal keratinocyte differentiation. The mutation affects calcium signalling in the ER, causing keratin filament collapse.
Reference: Neena Khanna Illustrated Synopsis of Dermatology & STD, 6th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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