Epidermal Variation: Skin Markings

Nevus (mole)

Commonly called a mole; a harmless overgrowth of melanin-forming cells.

What is the risk of a nevus becoming malignant (cancerous) ?

Rarely may become malignant.

Why should a nevus be monitored?

It should be monitored for changes suggesting malignancy.

Freckles

Yellowish or brown spots representing specific areas of increased melanocyte activity.

How do freckles form?

They occur where melanocytes are more active, producing extra pigment in that small area.

Factors affecting freckles

Sun exposure and heredity/genetics.

Effect of sun exposure on freckles

More sunlight causes skin cells to produce more melanin, making freckles darker.

Effect of heredity/genetics on freckles

Genes influence the number and darkness of freckles.

Hemangioma

Skin discoloration caused by a benign blood vessel tumor.

What two types of hemangioma are there?

Capillary and Cavernous hemangiomas

Capillary hemangiomas

Benign small blood vessel tumors that are bright red or purple at birth and often disappear in childhood. They are also called strawberry birthmarks.

Cavernous hemangiomas

Benign tumors made of larger blood vessels in the dermis that can last a lifetime. They are also called port-wine stains.