I. What diseases are included in vascular diseases? Vascular diseases are divided into two major categories: hemangiomas and vascular malformations. Vascular malformations are also divided into microvenous malformations (used to be called capillary hemangioma), venous malformations (used to be called cavernous hemangioma), arteriovenous malformations (used to be called trabecular hemangioma), lymphatic vascular malformations (used to be called lymphadenoma) and mixed malformations. Clinical manifestations of common vascular diseases 1.Hemangioma Infantile hemangioma is a benign tumor characterized by endothelial cell proliferation, with an incidence of 2% to 10% reported in the literature. About 1/3 of the lesions are present at birth and 2/3 of the lesions appear two weeks after birth, more in females than in males. The lesions appear to grow rapidly in stages until the child is one year old and stabilize after that. Hemangiomas that occur superficially on the skin are red in color and usually protrude from the skin surface. Hemangiomas that occur subcutaneously or under the mucosa tend to be cyanotic in color. Deeper hemangiomas tend to have normal skin color, and the lesions appear as moderately soft masses, usually in the parotid area. Most hemangiomas resolve spontaneously, but the length of the regression period varies, with the longest lasting until about 12 years of age. Some hemangiomas may leave skin pigmentation, skin atrophy and superficial scar after receding. Microvein malformation Microvein malformation consists of a large number of dilated microvessels, also known as erythematous nevus and wine stain, with an incidence of about 0.3%. Most of them are found in the skin of face and face, and also in the oral mucosa. Most of the lesions are present at birth and gradually expand with age and do not subside on their own. Microvenous malformations are pink, red or purple in color, and nodular or verrucous hyperplasia may appear in advanced stages. Venous malformations are composed of blood sinuses lined with endothelial cells. They are usually present at birth, grow gradually with age, and do not subside on their own. The skin and mucous membranes of venous malformations that occur in superficial areas appear blue or purplish-red. Lesions that occur deep in the face and neck appear as soft masses that increase significantly in size when the head is lowered. Blood clotting in the sinus cavity of the venous malformation may form a thrombus and calcify into a venous stone. Venous malformation can be accompanied by pain and bleeding, and extensive venous malformation often causes severe facial deformity and functional impairment. 4, arteriovenous malformation arteriovenous malformation is a kind of twisting and bending, extremely irregular and pulsating vascular malformation, mainly by the artery and vein with significantly dilated vessel wall direct anastomosis, mostly seen in adults. Clinically, it often presents as a localized pulsatile bulge with poorly defined boundaries. The lesion may be hyperplastic and then rosaceous, with normal or reddened surface skin color and high skin temperature. Patients may feel the pulsation themselves and have a tremor on palpation. The lesion invades the skin and thins it, and necrosis, rupture and hemorrhage may occur. The arteriovenous malformation may also erode the adjacent bone or occur in the jaw bone, and lesions occurring in the jaw bone may sometimes cause sudden gingival hemorrhage. 5.Lymphatic duct malformation Lymphatic duct malformation is a malformation formed by abnormal development of lymphatic ducts during embryonic period. It is mostly seen in children and adolescents. Most of the lesions are detected 1 to 2 years after birth and are found in the mucosal and submucosal layers of the head and neck and subcutaneously. They are divided into two types, microcystic and macrocystic, according to their structure. Microcystic lymphatics present as scattered clear or yellow or red blisters on the skin or mucosa. Large cystic lymphatic duct malformations are traditionally classified as cystic hydatid tumors and occur mostly in the neck. It is usually a multi-housed cystic cavity containing yellowish or bloody fluid. The lesion may suddenly swell and harden after internal bleeding or infection occurs.