Nevus pigmentosus et pilosus.

Area of Science:

• Dermatology
• Genetics
• Pediatrics

Background:

• Congenital melanocytic nevus (CMN) is a benign proliferation of melanocytes present at birth.
• Large CMN forms, affecting 0.002% of births, arise from NRAS/KRAS gene mutations during early pregnancy.
• Giant CMN, also termed 'bathing trunk nevus,' carries a significant risk of malignant transformation into melanoma.

Observation:

• A 7-year-old boy presented with itchy, progressively enlarging black patches on his back and shoulder since birth.
• Examination revealed extensive, well-demarcated hyperpigmented and hypertrichotic lesions covering the left shoulder, arm, trunk, nape, and entire back.
• Diagnosis of congenital melanocytic nevus was established based on clinical presentation.

Findings:

• Prophylactic surgery with skin grafting was recommended due to melanoma risk but declined by parents.
• Dermabrasion was performed to reduce pigmentation and hair growth.
• The patient received counseling on CMN complications and regular dermatological follow-up.

Implications:

• Early and meticulous examination of children with CMN is crucial for timely surgical intervention.
• Prompt management can significantly reduce the morbidity and mortality associated with congenital melanocytic nevus.
• This case underscores the importance of patient-physician communication regarding treatment options and long-term care for CMN.