This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
Keratoacanthoma is - 
Select and explain. 
A. A type of basal cell carcinoma, B. Infected sebaceous cyst, C. Self healing nodular lesion with central ulceration, D. Pre-malignant disease
C: Self healing nodular lesion with central ulceration
Answer: C: Self healing nodular lesion with central ulceration 
Explanation: • Keratoacanthoma is self healing nodular lesion with central ulceration
• More common in men, usually found on the face of 50–70 years old.
• Lesions can grow to 1–3 cm over 6 weeks and typically resolve spontaneously over the subsequent 6 months.
Etiopathogenesis
• Classically a cup-shaped growth that exhibits symmetry about its middle.
• Central crater is filled with a plug of keratin.
• Unclear etiology (may be caused by HPV infecting a hair follicle)
• Associated with smoking and chemical carcinogen exposure).
Treatment
• Removal of central keratin plug may speed resolution.
• Excision is recommended for persistent lesions
• Excision scar is often better than that which remains after resolution.