A congenital pigmented or melanocytic nevus is a dark-colored, often hairy patch of skin. A congenital nevus is present at birth or appears in the first year of life.
A giant congenital nevus is smaller in infants and children, but it usually continues to grow as the child grows. A giant pigmented nevus is larger than 8 inches once it stops growing.
Congenital giant pigmented nevus; Giant hairy nevus; Giant pigmented nevus; Bathing trunk nevus; Congenital melanocytic nevus – large
Causes, incidence, and risk factors
These marks are thought to be caused by problems that develop as a baby grows in the womb. In some families bathing trunk nevi may be inherited.
The condition may occur with:
Growth of fatty tissue cells (lipomas)
Smaller congenital pigmented or melanocytic nevi are common in children and do not cause problems most of the time. Larger or giant nevi are rare.
A nevus will appear as dark-colored patch with any of the following:
Brown to bluish-black color
- Regular or uneven borders
- Small satellite areas (maybe)
- Smooth, irregular, or wart-like skin surface
Nevi are commonly found on the upper or lower parts of the back or the abdomen. They may also be found on the:
Palms or soles
Signs and tests
You should have all birthmarks looked at by a health care provider. A skin
Your doctor will measure the dark skin area every year and take pictures to check if the spot is getting larger.
You will need to have regular exams to check for skin cancers.
Surgery to remove the nevus is be done if possible.
Treatment may be helpful if the birthmark causes emotional problems because of how it looks.
Skin cancer may develop in about 1 in 6 people with large or giant nevi. The cancer risk is higher for nevi located on the back or abdomen.
Depression and other emotional problems if the nevi affect appearance
Skin cancer (melanoma)
Calling your health care provider
This condition is usually diagnosed at birth. Talk to your child’s doctor if your child has a large pigmented area anywhere on the skin.