What term refers to the vascular birthmark made up of dilated blood capillaries that creates a reddish-purple discoloration?

The term that refers to a vascular birthmark characterized by dilated blood capillaries, resulting in a reddish-purple discoloration, is indeed the port wine stain. This type of birthmark is often present at birth and can be a prominent feature on the skin. Port wine stains occur due to the abnormal development of blood vessels, causing them to be enlarged (dilated) in a specific area, leading to the characteristic color. They typically appear on the face or other parts of the body and may darken or thicken as a person ages.

In contrast, naevae refer to moles or pigmented skin lesions that do not involve vascular components, while papillomas are benign tumors resulting from the proliferation of skin cells, often presenting as warts. Lentigo is characterized by flat, brown spots on the skin due to an increase in melanin, commonly associated with sun exposure and aging, which is unrelated to the vascular nature of port wine stains. This distinction helps clarify the unique attributes of a port wine stain compared to other skin conditions.