[A neonate with dark brown coloured buttocks and upper legs]

Area of Science:

• Dermatology
• Pediatrics
• Genetics

Background:

• Congenital melanocytic nevi (CMN) are benign pigmented skin lesions present at birth.
• Giant CMN are defined by their size and potential for widespread distribution.
• Early diagnosis is crucial due to associated risks.

Observation:

• A neonate presented with a well-defined macular hyperpigmentation in the genital area.
• The clinical presentation was consistent with a diagnosis of giant congenital melanocytic nevi (CMN).

Findings:

• Giant CMN occur in approximately 1 in 20,000 live births.
• A significant concern for patients with giant CMN is the potential development of neurocutaneous melanosis.
• There is an elevated lifetime risk of 5% for developing melanoma in individuals with giant CMN.

Implications:

• This case highlights the importance of recognizing and diagnosing giant CMN early in neonates.
• Monitoring for neurological complications and melanoma risk is essential throughout the patient's life.
• Further research into the management and long-term outcomes of giant CMN is warranted.