large congenital melanocytic nevus
Findings
No curated finding names large congenital melanocytic nevus yet. Everything below is reference data from Mondo, HPO and GenCC, not evidence about what affects it.
Definition
A large, or giant, congenital melanocytic nevus (LCMN or GCMN) is a pigmented skin lesion of more than 20 cm - or 40 cm- respectively, projected adult diameter, composed of melanocytes, and presenting with an elevated risk of malignant transformation.
Definition from the Mondo Disease Ontology (MONDO:0044792), read 2026-09-29. CC BY 4.0.
- Inheritance
- Typified by somatic mosaicism
HPO, annotations 2026-09-02
Features
21 features
What the disease is reported to present with, and how often among people who have it — never how often a feature means the disease. HPO, annotations 2026-09-02.
- Abnormal skin pigmentationHPOHP:0001000
- Very frequent (80% to 99% of cases)
- Congenital giant melanocytic nevusHPOHP:0005600
- Very frequent (80% to 99% of cases)
- NevusHPOHP:0003764
- Very frequent (80% to 99% of cases)
- AnhidrosisHPOHP:0000970
- Frequent (30% to 79% of cases)
- Dry skinHPOHP:0000958
- Frequent (30% to 79% of cases)
- Poor wound healingHPOHP:0001058
- Frequent (30% to 79% of cases)
- Atypical behavior
Show the remaining 9
- Increased intracranial pressureHPOHP:0002516
- Occasional (5% to 29% of cases)
- Neurodevelopmental delayHPOHP:0012758
- Occasional (5% to 29% of cases)
- PruritusHPOHP:0000989
- Occasional (5% to 29% of cases)
- SeizureHPOHP:0001250
- Occasional (5% to 29% of cases)
- Spinal cord compressionHPOHP:0002176
- Occasional (5% to 29% of cases)
- Subcutaneous noduleHPOHP:0001482
- Occasional (5% to 29% of cases)
Genes
1 gene
Germline variants in the gene encoding each protein, as classified by GenCC submitters, each in their own words. Limited, disputed and refuted submissions are listed too.
- BRAFHGNC:1097
- Strong · PanelApp Australia · Autosomal dominant · 2025
Where it sits
Other names
19 names
Resolves to: large congenital melanocytic nevus
- Also called
- bathing trunk nevuscongenital melanocytic nevicongenital melanocytic nevuscongenital melanocytic nevus of skincongenital melanocytic nevus of the skincongenital nevus of skincongenital nevus of the skincongenital pigmented melanocytic Nevuscongenital pigmented nevus of skincongenital pigmented nevus of the skincongenital pigmented skin nevuscongenital skin nevusGiant Congenital Melanocytic Nevusgiant congenital nevusgiant pigmented hairy nevus