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A vascular anomaly is a kind of birthmark caused by a disorder of the vascular development, although it is not always present at birth. A vascular anomaly is a localized defect in blood vessels that can affect each part of the vasculature (capillaries, arteries, veins, lymphatics or a combination of these). These defects are characterized by an increased number of vessels and vessels that are both enlarged and sinuous. Some vascular anomalies are congenital and therefore present at birth, others appear within weeks to years after birth and others are acquired by trauma or during pregnancy. Inherited vascular anomalies are also described and often present with a number of lesions that increase with patients’ age. Vascular anomalies can also be a part of a syndrome and, occasionally, they can be acquired by trauma. The estimated prevalence of vascular anomalies is 4.5%. Vascular anomalies can occur throughout the whole body (skin, bone, liver, intestines, i.e.), but in 60% of patients vascular anomalies are localized in the head and neck region. Vascular anomalies can present in various ways. Vascular anomalies that are situated deep below the skin, appear blue and are often called cavernous. Superficial vascular anomalies appear as red-coloured stains and are associated with vascular anomalies affecting the dermis. Historically, vascular anomalies have been labeled with descriptive terms, according to the food they resembled (port wine, strawberry, cherry, salmon patch). This imprecise terminology has caused diagnostic confusion, blocked communication and even caused incorrect treatment, as it does not differentiate between various vascular anomalies. However, in 1982, Mulliken introduced a classification that replaced these descriptive terms and gave direction to the management of various vascular anomalies. This classification, based on clinical features, natural history and cellular characteristics, divides vascular anomalies into two groups: vascular tumors and vascular malformations. Although the appearance of both vascular tumors and vascular malformations can resemble, there are important differences between both. 〔 ==Vascular tumors== Vascular tumors, often referred to as hemangiomas, are the most common tumors in infants, occurring in 1-2%. Prevalence is even higher (10%) in premature infants of very low birth weight.〔 Vascular tumors are characterized by overgrowth of normal vessels, which show increased endothelial proliferation. It can be present at birth, but often appears within a couple of weeks after birth or during infancy. There are different kinds of vascular tumors, but the 4 most common types are: infantile hemangioma, congenital hemangioma, kaposiform hemangioendothelioma and pyogenic granuloma. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「vascular anomaly」の詳細全文を読む スポンサード リンク
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