True hemangioma is a vascular developmental abnormality seen in infants within 1 year of age and can occur in the skin, subcutis and organs, with the cutaneous type being the most common. They first appear at birth – within 2 months, undergo a rapid growth period of several months, and reach maturity within 1 year of age, after which they begin to resorb on their own and last for 3-5 years, up to 12 years. It occurs mostly in female infants, accounting for about 85% of cases. [Diagnosis] 1. Natural course and clinical manifestations: Typical true hemangiomas are most often seen within the first 2 months of life as erythema or capillary dilatation surrounded by a white halo, or blotches. In the following rapid growth period, the tumor grows rapidly, brightens in color, and forms a distinct mass, which has some tension and does not fade due to compression, and the surrounding perfused vessels can be seen. After 1 year of age, it begins to remit, showing a shrinking of the tumor and a gradual progression of the pigmentation to normal. However, some patients flow with sequelae such as hyperpigmentation, capillary dilatation, keratinization, and scarring. 2.Pathological features: The pathological features of true hemangioma are chaotic growth of vascular endothelial cells, microscopically visible accumulation of multilayered basement membrane under endothelial cells, and extracellular interstitium may have a large amount of expression of pro-angiogenic factors. 3.MRI and CT: True hemangioma may appear as a substantial mass with envelope in both CT and MRI, and the signal intensity is uneven and can be enhanced, and it has specific performance in MRI: flowing fluid can be found in the mass with thickened trophoblastic vessels. After intravenous injection of gadolinium enhancement agent, the tumor showed uniform signal intensity. Doppler ultrasound: This is an inexpensive, non-invasive test. True hemangiomas can show high blood flow velocities, although they are sometimes confused with arteriovenous fistulas. 5.Some other tests: When patients present with symptoms such as blindness/airway obstruction, a careful examination of vision, fundus, and airway is needed to facilitate preoperative evaluation. [Differential diagnosis] True hemangioma is mainly distinguished from other masses with abnormal vascular development in infants and children: 1. Vascular malformation: Vascular malformation is caused by the disorganized arrangement of blood vessel growth and is not accompanied by high expression of pro-angiogenic factors. Vascular malformations can also have early manifestations such as erythema at birth, but do not grow rapidly in early infancy and early childhood. After puberty, the masses show relatively slow growth without eventual self-absorption, but the masses are soft in texture and can fade when pressed. Under CT and MRI, it shows a large number of vascular shadows, but does not show a substantial mass. 2.Inflammatory sarcoidosis: It occurs mostly in school age and starts rapidly after trauma, on which there may be ulcers and purulent material secretion. 3, hemangioendothelioma: It can occur at all ages after birth, mostly on the trunk and extremities, unlike true hemangioma which occurs on the face, and the mass is lavender in color and unusually hard in texture. Histologically, the masses show irregular lobules and cell plates invading the dermis and subcutaneous fat layer, with spindle-shaped endothelial cells, microthrombosis, iron deposits, and a decrease in epithelial cells and giant cells. The growth is very rapid and the prognosis is extremely poor. 4. Congenital hemangioepithelioma: It is a rare benign hemangioepithelioma, mostly growing at the end of the limbs of newborns and young children, and pathological diagnosis is an important means of identification. [Treatment] Due to the self-limiting growth of true hemangioma, the vast majority of patients do not require special treatment, and necessary explanation to the parents of the child is necessary after a clear diagnosis. Approximately 10-20% of children require treatment, which is indicated by the abnormally rapid growth of the tumor and the presence of a true hemangioma in the viscera, leading to some of the obvious aforementioned complications. Glucocorticosteroids: The drug of choice is oral prednisone 2-3 mg/kg/d for 6 weeks and then gradually reduced, and the duration of the drug should be extended for visceral true hemangioma. Glucocorticoids are more effective for hemangiomas in the growth phase. Intraocular hemangioma can be treated with intravitreal injection of hormone. The main side effects of glucocorticoid treatment are developmental delay and Cussion syndrome. 2. α-interferon: This is an effective drug that can inhibit angiogenesis, especially its subtype 2a. The recommended dose is 3 million units/square meter of body surface area injected subcutaneously daily for 6-14 weeks, which can be effective in cases where glucocorticoids are ineffective. The main side effects are granulocytopenia, fever, hypothyroidism and neurological damage (spastic paralysis). 3.Laser treatment: Laser treatment cannot stop the growth of the tumor and mainly helps those patients who cannot tolerate the long time for the tumor to subside on its own and those who have a large area covered by the tumor. For hemangioma with ulcers, laser treatment can promote healing and reduce pain. Cryotherapy: Cryotherapy is good for tumors that are not very fast-growing, but may cause scars that are difficult to heal, leading to the need for eventual surgery. 5.Surgical excision: The indications for surgical excision are that the tumor is growing in the eyelid or nasal cavity, resulting in impaired vision or breathing. Late surgical treatment is to remove the posterior scars after the tumor has healed itself.