A hemangioma or haemangioma is a usually benign vascular tumor derived from blood vessel cell types. The most common form, seen in infants, is an infantile hemangioma, known colloquially as a "strawberry mark", most commonly presenting on the skin at birth or in the first weeks of life. A hemangioma can occur anywhere on the body, but most commonly appears on the face, scalp, chest or back. They tend to grow for up to a year before gradually shrinking as the child gets older. A hemangioma may need to be treated if it interferes with vision or breathing or is likely to cause long-term disfigurement. In rare cases internal hemangiomas can cause or contribute to other medical problems. They usually disappear by 10 years of age. The first line treatment option is beta blockers, which are highly effective in the majority of cases. Hemangiomas present at birth are called congenital hemangiomas, while those that form later in life are called infantile hemangiomas.

Hemangiomas are benign (noncancerous) vascular tumors, and many different types occur. The correct terminology for these hemangioma types is constantly being updated by the International Society for the Study of Vascular Anomalies (ISSVA). The most common are infantile hemangiomas, and congenital hemangiomas.

Infantile hemangiomas are the most common benign tumor found in children. They are made up of blood vessels, often called strawberry marks, and are more common in girls than in boys. Babies that are born early are more likely to have a hemangioma. They usually appear on the skin of infants in the days or weeks after birth. They tend to grow quickly for up to a year. Most then shrink or involute without further problem, however some can ulcerate and form scabs which can be painful. Depending on their location and size, they may also be disfiguring.

Rarely, they may be related to disorders of the central nervous system or spine. They may also occur in the internal organs of the body, such as the liver, airway or brain.

The color of the hemangioma depends on how deep it is in the skin: superficial (near the skin's surface) hemangiomas tend to be bright red; deep (furthest from the skin's surface) hemangiomas are often blue or purple; mixed hemangiomas may have colors of both superficial and deep.

Congenital hemangiomas are present on the skin at birth, unlike infantile hemangiomas, which appear later. They are fully formed at birth, meaning that they do not grow after a child is born, as infantile hemangiomas do. They are less common than infantile hemangiomas. Congenital hemangiomas can be coloured from pink to blue.

Congenital hemangiomas are classified according to whether they shrink and go away, or do not shrink, and do not go away, or partially shrink. Those that shrink are known as rapidly involuting congenital hemangiomas (RICH) and go away quickly. Those that do not shrink, and remain are known as noninvoluting congenital hemangiomas (NICH). Others that partially shrink are known as partially involuting congenital hemangiomas (PICH).

Other types of hemangioma include cavernous hemangiomas such as cavernous hemangioma of the liver.