Alternative Names giant naevus, giant hairy naevus
Definition A giant naevus is a large, pigmented, mole-like birthmark. It covers an extremely large area of the body, often in the area covered by a pair of bathing trunks. It is often covered with hair.
What is going on in the body? A collection of mole, or naevus, cells forms a very large brown mole during foetal development. The giant naevus is present at birth.
What are the signs and symptoms of the condition? Symptoms of a giant naevus may include:
a brown mole-like birthmark covering an extensive area of the trunk or legs
hair growing from the mole
smaller lesions near the large mole
surface texture varying from smooth to warty
colour varying from brown to blue-black
What are the causes and risks of the condition? Although the cause of giant naevi is unknown, there may be a hereditary factor in some cases.
What can be done to prevent the condition? There is no known prevention for a giant naevus.
How is the condition diagnosed? The doctor can diagnose a giant naevus when he or she examines the characteristic birthmark. A biopsy may be done to determine if the cells have become cancerous.
What are the long-term effects of the condition? A giant naevus may develop into melanoma, a particularly serious form of skin cancer. The cosmetic appearance may cause psychosocial problems.
What are the risks to others? There are no risks to others.
What are the treatments for the condition? The lesion must be carefully monitored for any changes in colour or texture. Surgery to remove the naevus may be recommended to prevent the development of melanoma.
What happens after treatment for the condition? After the naevus is removed, the area needs to be watched closely for signs of infection.
How is the condition monitored? A giant naevus should be closely monitored by the doctor. The affected person, or the family, should report any changes in texture or colour to the doctor.
Author: Lynn West, MD Reviewer: HealthAnswers Australia Medical Review Panel Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia Last Updated: 1/10/2001 Contributors Potential conflict of interest information for reviewers available on request
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