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Common Birthmarks - Symptoms


Nevus sebaceous occurs most commonly on the face and scalp. They appear as solitary or several, yellow to tan, hairless plaques. Lesions may be oval or linear, and can vary in size from a few millimetres to several centimetres. The surface may be smooth, velvety or more warty.

Secondary tumours may occur within NS, most of which are benign. Basal cell carcinoma, a low-grade skin cancer can rarely occur, usually after puberty.

If a new nodule appears in a previously stable NS, your dermatologist may recommend a biopsy to exclude a secondary tumour.


EN appear as tan to brown, velvety or warty plaques, and may be single or multiple. Although most commonly seen on the limbs, they may occur anywhere on the skin. They may occur in a linear or wavy pattern.


CMN appear as flat or slightly raised light to dark brown lesions. Pigment variation and increased hairs may be seen. With time, they can become thicker. Large CMNs may have a rough cobbled-stone surface and more colour variability.

There is a slightly increased risk of cancerous change (malignant melanoma) in all CMN. However, the risk is small in small and medium sized CMN. The risk is higher in large CMN, and can occur earlier.

Large CMN are also associated with increased risk of involvement of the nervous system (brain or spine).

Common Birthmarks - How to prevent?

Common Birthmarks - Causes and Risk Factors

Common Birthmarks - Diagnosis

Common Birthmarks - Preparing for surgery

Common Birthmarks - Post-surgery care

Common Birthmarks - Other Information

The information provided is not intended as medical advice. Terms of use. Information provided by SingHealth

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