Chapter 8: Lumps and Bumps
Melanocytic Lesions: Melanoma
What is it?
Melanoma is the most dangerous form of skin cancer. Fortunately, it is rare in children, with only 1-3% of all melanoma cases occurring under 20 years of age. The cause of melanoma is multifactorial with both genetics and environmental exposure (most importantly UV light) playing a role. Malignant melanoma is most common in light skinned patients. When melanoma occurs in patients with skin of colour it is usually on acral surfaces or the nail beds.
What does it look like?
In adults and older children, melanoma follows the ABCDE criteria. In children under 12, amelanotic melanoma is more common. These generally present with a new and growing pink papule that bleeds. They are often misdiagnosed and so any such lesion that is removed should be submitted to pathology.
The ABCDE’s of Melanoma in Adults:
Asymmetry: The colour is not uniform across the mole and the shape is not symmetric
Border irregularity: The mole has variable edges including scalloping or notches and may have projections growing off to the side.
Colour variability: The mole has multiple colours or shades of colour within it. It may be brown, black, red, white, or even blue.
Diameter: Mole is >6mm in width.
Evolving: Growing and changing in size or shape.
How is it treated?
A suspected melanoma should be biopsied with a 1-2mm clinical margin, but is likely to require re-excision of the pathology confirms melanoma. Fortunately, the prognosis for children with melanoma is generally better than that for adults. A complete work-up with by dermatology in conjunction with medical oncology is generally recommended to determine the need for systemic therapy and direct therapy choices. Close follow-up is indicated for patients with previous melanoma who are at highest risk of developing a second melanoma in the first 2-3 years after diagnosis.
