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: Pathology
Malignant transformation to melanoma is common in: March 2009 
Select and explain. 
A. Dermal nevus, B. Junctional nevus, C. Congenital nevus, D. Lentigo nevus
B: Junctional nevus
Answer: B: Junctional nevus 
Explanation: Ans. B: Junctional nevus Intradermal nevus: Benign; Junctional nevus: Premalignant: source for most malignant melanomas; looks like intradermal nevus but larger, often ulcerated, irregular border and heterogeneous coloration. Suspect melanoma if junctional nevus is getting darker or larger or bleeding or itching. Spitz nevus/spindle and epithetliod cellnevus is a red-pink nodule; often confused with hemangioma clinically Blue nevus is black-blue nodule; often confused with melanoma clinically