Venous lake

Content sourced from Wikipedia, licensed under CC BY-SA 3.0.

Venous lake is a small, soft, dark blue to purple bump that appears on sun-exposed skin. It’s most commonly found on the vermilion border of the lip, but can also occur on the face or ears. The lesion is usually solitary and measures about 0.2 to 1 cm. It tends to appear in older adults and is sometimes referred to as phlebectasis.

Cause
The exact cause isn’t known, but sun exposure is thought to play a role. This may enlarge a small blood-filled channel in the skin.

What it is
Venous lake is a vascular (blood vessel) lesion. Under the skin, it’s a dilated blood-filled channel lined by a single layer of endothelial cells and a thin wall of tissue. The bump is typically compressible and has a dark blue-purple color.

How it is told apart from melanoma
Venous lake can look similar to nodular melanoma, but it usually does not feel firm (no induration), grows slowly, and lightens with a test called diascopy. It also does not pulsate, which helps distinguish it from a nearby artery.

Treatment
People may seek treatment for cosmetic reasons. Surgical removal works but can leave a scar. Today, laser therapy is the preferred treatment. Long-pulsed Nd:YAG laser is highly effective, with about 94% of cases clearing after a single treatment in studies, and most patients have no scarring or complications afterward.

History
The name “venous lake” was coined by American physician William Bennett Bean.

Images and further reading
There are photographs showing venous lakes on the ear and other sun-exposed areas, but these are optional for a quick understanding.