In Darier's disease (keratosis follicularis), the histopathological finding of 'corps ronds' and 'grains' are pathognomonic. Corps ronds are found in:
- A Upper spinous/granular layer — large, rounded dyskeratotic cells with pyknotic nucleus surrounded by clear halo ✓
- B Stratum corneum — large cells with shrunken dark nuclei surrounded by clear halo
- C Basal layer — acantholytic cells with suprabasal cleft
- D Dermis — multinucleate cells with foreign body reaction
Explanation
Darier's disease (ATP2A2 mutation — SERCA2 pump defect causing impaired intracellular calcium signaling) shows characteristic histopathology: (1) Corps ronds — large rounded dyskeratotic cells in the upper spinous and granular layers with a pyknotic nucleus, perinuclear pale halo, and dense keratinized cytoplasm; (2) Grains — small elongated parakeratotic cells in the stratum corneum; (3) Suprabasal acantholysis forming 'villi' covered by a single layer of cells; (4) Lacunae (clefts). Corps ronds in the granular layer are the pathognomonic feature distinguishing Darier's from Hailey-Hailey disease.
Reference: Neena Khanna Illustrated Synopsis of Dermatology & STD, 6th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.