This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Surgery
True about this condition is 
Select and explain. 
A. Hamaoma of naevo-melanocytes, B. Increased risk of squamous cell carcinoma, C. Limited to dermis, D. Regress completely by 7 years
A: Hamaoma of naevo-melanocytes
Answer: A: Hamaoma of naevo-melanocytes 
Explanation: This is Giant congenital pigmented naevus (GCPN) or giant hairy naevusIt is a hamaoma of naevo-melanocytes that has a tendency to dermatomal distribution. It has a similar histology to compound naevi, but the naevus cells are distributed variably from the epidermis throughout all layers and into the subdermal fat and muscle. GCPNs are precursors of melanoma. A 3-5% lifetime risk of melanoma is quoted. 1 in 3 childhood malignant melanomas (MM) arise in patients with GCPN.A Mongolian spot, a congenital blue-grey macule found on the sacral skin regresses completely by age 7 years.Ref: Bailey and love, 27e, page: 601