Acquired hemangioma is an abnormal proliferative disease of blood vessels due to acquired causes. Common types include septic granuloma, microvenous hemangioma, target-like iron-containing heme deposition hemangioma, verrucous hemangioma, acquired elastic tissue degenerative hemangioma, cherry-colored hemangioma, plexiform hemangioma, acquired multiple hemangiomatosis, etc. 1.Purulent granuloma can be seen in the gum tissue, lips, skin of the face or oral mucosa, similar in appearance to a mucosal polyp, bright red, smooth surface, and may have a tip. It consists of multiple lobular tissues composed of proliferating vascular endothelial cells, resembling granulation tissue, which contains inflammatory cell infiltration, hence the name septic granuloma. As the hemangioma grows, the vascular component in it gradually decreases, and then fibrosis occurs. Microvascular hemangioma is a newly reported benign vascular tumor, first described and named by Hunt et al. in 1991, which is a rare lesion, but Bantel et al. reported a microcapillary hemangioma in 1989, so the two may belong to the same lesion. The clinical presentation is usually an isolated purple or red nodule, or small plaque or papule-like lesions, 0.3-2.0 cm in diameter, with a short duration of disease, usually a few months, or up to 4 years. The most common sites of disease are the limbs, especially the forearms, followed by the trunk and lower legs. The majority of patients are young people, and both sexes can develop the disease. It is often diagnosed clinically as a hemangioma and sometimes misdiagnosed as Kaposi’s sarcoma. The histology of microvascular hemangioma is characterized by tumors located in the dermis and composed of small, thin-walled blood vessels that are proliferating. These small vessels are characteristically irregularly branched and grow infiltratively throughout the dermis. The luminal spaces of the vessels are often narrow. The endothelium may sometimes be slightly obese, round or ovoid, but without heterogeneity, and nuclear schizotypy is rare or absent. Another characteristic of the disease is that perivascular cells are seen at the periphery of the endothelium. In addition, the stroma between the vessels is often associated with marked collagen-like degeneration, hence the name pro-connective tissue hemangioma. Except for a few lymphocytes and mast cells, there is no obvious inflammatory reaction in the interstitium, and there is no erythrocyte exudation or iron-containing hemoglobin deposition. Immunohistochemical markers show that endothelial cells are strongly positive for endothelial markers such as FⅧ, CD31, CD34, and U EA-1, while perivascular cells are located in the dermis and formed by the proliferation of small vessels, which have thin, branching walls, irregular morphology, and infiltrative growth characteristics. Although microvascular hemangioma is composed of small blood vessels, the lumen of the vessels is extremely fine and almost devoid of red blood cells, thus it is called microvascular hemangioma. The nature of the blood vessels in microvascular hemangioma is unknown and may belong to a small vein. Microvascular hemangioma is a benign tumor and can be cured after local excision. 3.Target-like hemosiderin-containing hemangioma, also known as stud-like hemangioma, is a benign vascular tumor of the skin with a target-like appearance, first reported by Santa Cruz and Aronberg in 1988. It is usually seen in young to middle-aged males, often on the extremities, and presents as a target-like lesion, usually with a purple-red or brown papule < 2 cm in diameter at the center of the target that grows slowly and has no conscious symptoms; the surrounding skin is tan or normal in color, surrounded by a ring of stasis at the outermost periphery, which may expand outward on its own and gradually fade in color until it completely resolves, but the purple-red papule or nodule at the center of the target often persists. Untreated THH lesions may persist for 1 month to 2 years, during which time the pattern of THH lesions may change in phases or cycles. The histopathology of the disease is characterized by irregular dilatation of the superficial dermal vascular lumen and swelling of the endothelial cells in the vessel wall, resembling shoe nails protruding into the lumen; lymphocytic infiltration around the superficial and middle dermal vessels and iron-containing heme deposits are seen. The disease should be differentiated from nevus pigmentosus, melanoma, Kaposi's sarcoma and angiokeratoma. Surgical excision is preferred for treatment. 4.Wart hemangioma is a rare vascular malformation that develops at birth or in childhood. The etiology and pathogenesis are unknown. The typical lesions are unilateral, grouped, scattered or fused keratotic vascular papules, sometimes linear or creeping. The early lesions are pale blue, well-defined, soft, and gradually enlarge to satellite nodules, followed by surface keratinization into warts. The most common site is the lower extremities, especially the distal lower extremities. The main use of CO2 laser therapy, cryotherapy or surgical excision, excision should be deeper to avoid recurrence. 5. Acquired elastic tissue degenerative hemangioma Six cases were first reported by Requena et al. in 2002, and 14 cases were reported by Martorell-Calatayud et al. in 2010. It is common in middle-aged and elderly women, with an age of onset of 63-76 years, a mean of 64 years, and a disease duration of several years. The tumor is usually found on skin that is easily exposed to the gaze (such as the radial side of the forearm or the side of the neck) and has a single red papule-like appearance with various and irregular morphology, but rarely has a hemangioma appearance, so it is easily misdiagnosed as basal cell carcinoma, Bowen's disease and lupus erythematosus. The tumor is 2-5 cm in diameter, with clear borders and purplish red color. Microscopically, the tumor is located in the superficial dermis, with capillary hyperplasia in the form of bands parallel to the epidermis; elastic tissue is degenerated, and fibers are tightly attached to the epidermis, separating the blood vessels from the epidermis and encircling or interspersed around the blood vessels; capillaries are nodular, vessels are round or lacunar, covered with single layer of vascular endothelial cells, nuclear anomalies and nuclear division are rare, without traffic-like vascular lumen and erythrocyte extravasation, but some cases are occasionally seen with lymphocyte-based infection. Lymphocyte-dominated infection was occasionally seen in some cases. Immunophenotype: α-SMA-positive perivascular epithelial cells, CD31, CD34 and D2-40 positive endothelial cells, Ki-67 and MPM-2 showed weak proliferation of tumor cells. Differential diagnosis: early Kaposi's sarcoma, extremity dermatitis. No recurrence of the tumor is reported in the literature. 6.Cherry-colored hemangioma, also known as senile hemangioma, is one of the common acquired hemangiomas. It can appear in early adulthood and increases with age, mainly in the trunk, but rarely in the hands, feet or face. Its etiology is unclear. The clinical manifestations are ovoid or round, 0.5-0.6mm in diameter, deep red papules, soft and hemispherical in shape above the skin surface. The number varies. Usually no treatment is needed, but laser or surgical treatment is feasible if necessary. 7. Plexiform hemangioma, also known as acquired plexiform hemangioma or plexiform hemangioblastoma, is a rare benign vascular proliferation disease, named after its histopathological manifestation of scattered plexiform or massive capillaries in the dermis. It is most commonly seen in children and adolescents, and is more common under the age of 5 years, or at birth, and occasionally in the elderly. The incidence is equal in both sexes, and there is no apparent familial tendency, but there are reports of concentrated familial incidence. It is characterized by slowly expanding dark red papules or plaques, 2-5 cm in size, with indistinct boundaries, sometimes accompanied by subcutaneous nodules. Most patients have pain, probably related to localized myoepithelial contraction and spasm of the vascular wall, which is more markedly affected by temperature or mechanical pressure stimulation. The disease lasts for about 0. 5 to 10 years during the growth phase, followed by a stable phase. A few patients have localized spontaneous regression, but it usually slowly increases with body growth, and most patients show persistent and lifelong presence. The diagnosis is based on the histopathological features of the lesions and requires differentiation from Kaposi's granuloma, low-grade malignant angiosarcoma and infantile hemangioma. They can be treated with drugs, laser or surgery.