There is no unified standard for clinical classification of hemangioma, and there are mainly two classification methods as follows: 1. Morphological classification It is a classification method based on histological structure and clinical signs. It classifies hemangiomas into capillary hemangiomas (nevus and strawberry hemangioma), cavernous hemangiomas, trabecular hemangiomas and mixed hemangiomas. This classification method is still used in most textbooks. (1) Capillary hemangioma: Mostly seen in infancy and early childhood, occurring in superficial parts of the face and oral mucosa. It is composed of proliferating capillaries, most commonly strawberry-shaped, slightly above the surface, bright red or purple-red in color, with clear borders and receding color when pressed, called strawberry capillary hemangioma. If it does not rise above the surface and appears as a large flat red spot, it is called wine spot. (2) Spongiform hemangioma: It is found in the deep part of the face and oral mucosa and consists of enlarged venous ducts or sinus cavities. The lesion is elevated on the skin or mucosal surface and expands to deeper tissues. The lesion is greenish-blue in color, irregular in shape, uneven on the surface, soft like sponge, shrinks when pressed, returns to its original shape immediately after pressure is removed, and increases when the head is low. Hard nodular venous stones can be felt and blood can be extracted by puncture. It can involve the jaw bone and affect the facial appearance, causing facial deformity and dysfunction. (3) Trapezoid hemangioma: It is a vascular malformation with direct communication between arteries and veins. The dilated blood vessels under the skin of the lesion area are trapezoidal and tortuous, with obvious pulsation and tremor, and a blowing murmur on auscultation, and the surface skin is dark red. (4) Mixed hemangioma: Mixed hemangioma consists of simple and cavernous hemangioma, and the clinical manifestations are the same as the above two types of hemangioma. 2.Cytological classification (new classification method) In 1982 Mulliken divided traditional hemangioma into two categories: hemangioma and vascular malformation by culturing specimens of vascular endothelial cells in hemangioma and finding that they have the dual characteristics of tumor and malformation. Hemangioma: It is characterized by the proliferation of vascular endothelial cells and the formation of a large number of new capillaries, with clinical manifestations of strawberry hemangioma, cavernous capillary hemangioma and mixed hemangioma. Pathogenesis: It may be caused by increased levels of pro-angiogenic factors and decreased levels of growth inhibitory factors Vascular malformation: It is a developmental malformation of the vascular system with predominantly blood vessels, while the vascular endothelial cells are normal. They are further classified according to anatomical and rheological features: low-flow vascular malformations: including capillary malformations, venous malformations and lymphatic malformations; high-flow vascular malformations: including arteriovenous malformations, arteriovenous malformations and arteriovenous fistulas.