Which premalignant epidermal lesion is considered the most common precursor of invasive cutaneous squamous cell carcinoma in chronically sun-exposed skin?
- A Actinic keratosis ✓
- B Seborrheic keratosis
- C Melanocytic nevus
- D Epidermal nevus
Correct answer: A. Actinic keratosis
Explanation
Actinic keratosis is a keratinocyte dysplasia induced by cumulative UV damage, showing atypical basilar keratinocytes with parakeratosis, and a small proportion progress to invasive squamous cell carcinoma each year. It is the commonest precursor lesion in sun-damaged skin. Seborrheic keratoses are benign acanthotic tumours that never transform, and epidermal nevi are hamartomatous malformations rather than dysplasias.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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