A newborn has this truncal lesion. The initial step in management of this infant with a pigmented skin lesion is

 

 

A magnetic resonance imaging (MRI).

 

B dermabrasion.

 

C laser ablative therapy.

 

D excision of the entire lesion and immediate skin grafting.

 

E serial excision and reconstruction.​

A

A

A

A

Correct answer

A magnetic resonance imaging (MRI).

 

Congenital melanocytic nevi (CMN) are darkly pigmented, vary in size and occur in any part of the body. Giant congenital nevi (GCN) are those that are twenty cm in diameter or occupy greater than two percent body surface area. The lifetime malignant transformation risk within a giant congenital melanocytic nevus is between zero to five percent in small nevi and five to 10% in larger nevi. In larger CMNs, melanoma develops deep to the dermal epidermal junction. When melanoma occurs, it tends to occur in the trunk, head and neck or extracutaneously such as the central nervous system or retroperitoneum; 70% occur within the first decade of life. Features that may suggest dysplasia or neoplasia include irregular borders, nodularity, ulceration and uneven pigmentation; these lesions should be biopsied or removed sooner, if possible. If a GCN crosses the midline, neurocutaneous melanosis should be suspected and an MRI should be performed to rule out neural involvement.

 

Treatment regimens that have been described for GCN include excision, dermabrasion, chemical peel, laser ablation and Moh’s microscopic surgery. The contemporary principles in dealing with this problem include reduction of malignant risk while preserving function and cosmesis. Surgical excision is the only modality that eradicates all malignant cells. Since the surface area of these lesions is large, excision is usually done serially. Time between excisions allows stretch to occur in the surrounding skin. Tissue expanders may be used to achieve full closure after excision, but is recommended only if the entire lesion cannot be excised in two to three stages. Tissue expanders are best tolerated in the trunk and scalp area.

 

At the time of excision, it should be noted that the melanocytes can go beyond the dermis into the fat or the subcutaneous tissue. Care should be exercised in making sure that the deep margins of the lesion are clear. If melanocytic cells remain in the deep margin, surveillance of the lesion would be impossible and the risk of future malignant transformation would be difficult to monitor. Dermabrasion, chemical peel and laser peels do not completely remove the nevus cells and lightening the nevus give rise to concerns or difficulties with monitoring changes in the cells.