This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Papulosquamous disorders, Subject name: Dental
Flat topped violaceous papule, thinning of nail.Microscopic finding would be? 
Select and explain. 
A. Basal cell degeneration, B. Epidermal bulla, C. Acantholysis, D. Prominent necrotic cells
A: Basal cell degeneration
Answer: A: Basal cell degeneration 
Explanation: As per the clinical features,flat topped papules with thinning of nails are characteristc of lichen planus LICHEN PLANUS:- Histology:-1. Irregular acanthosis of the epidermis.2. Hypergranulosis 3. Compact hyperkeratosis.4. Basal cell damage.5. Colloid bodies6. Pigment incontinence.7. Band like lympho histiocytic infiltrate obscuring the dermoepidermal interface. IADVL TEXTBOOK OF DERMATOLOGY PAGE 1070