VASCULAR LESIONS Congenital haemangiomata and vascular malformations

VASCULAR LESIONS Congenital: haemangiomata and vascular malformations

These can be subclassified biologically into vascular tumours or vascular malformations based on their endothelial charac - teristics, or radiologically into haemangiomata, vascular and lymphatic malformations based on their vascular dynamics. Haemangiomata These are benign endothelial tumours that a ff ect three girls for every boy . Thirty per cent have a herald patch at birth, which then grows rapidly in the first year of life and slowly involutes over several years, with 70% having resolved by 7 /uni00A0 years of age. Large haemangiomata can trap platelets, leading to thrombocytopenia (Kasabach–Merritt syndrome). Vascular malformations Vascular malformations a ff ect boys and girls equally and are associated with numerous syndromes. They are invariably present at birth but may be missed if deep to the skin. Vascular malformations subsequently grow in proportion to the child’s growth (rather than in response to sepsis or hormonal stimula tion). Stasis can lead to a localised, consumptive coagulopathy in large venous malformations. Low-flow malformations may cause skeletal hypoplasia, while high-flow malforma tions can cause hypertrophy .

Figure 45.41 Merkel cell tumour (courtesy of St John’s Institute for Dermatology, London, UK).