[Classification of superficial vascular anomalies]

Abstract

All superficial vascular abnormalities are not angiomas even though this term continues - incorrectly - to be used. Because the suffix "oma" implies a tumor, it is necessary to differentiate true vascular tumors, such as infantile hemangioma, from vascular malformations. From a hemodynamic perspective, there are two types of vascular malformations: slow- and fast-flow. In addition to the functioning of the impaired or severely damaged vessels, we discuss slow-flow capillary, venous, or lymphatic malformations and rapid flow arterial and arteriovenous malformations. All combinations are possible. There are several types of childhood vascular tumors with different courses and different prognoses. Infantile hemangioma is by far the most frequent (8 to 10 children/100). The diverse other vascular tumors in children are sufficiently rare that they are described as orphan diseases. Since the end of the last century, a simple endothelial marker, GLUT-1, is available. This immunophenotype is present in all cases of infantile hemangioma at every stage and is negative in other tumors. Kasabach-Merritt syndrome and its accompanying severe thrombocytopenia never complicate childhood hemangioma, contrary to what has been said for nearly 60 years. When it is present, the tumor is either a tufted angioma or kaposiform hemangioendothelioma, and the GLUT1 marker can distinguish them from infantile hemangioma if the histologic diagnosis is uncertain (GLUT 1 is negative in both the latter cases). There are a wide variety of rare vascular tumors; many of them are benign, isolated, or limited; some are locally aggressive and recur after excision. A small number are low-grade malignant lesions with a risk of multivessel expansion, metastasis, and sometimes a fatal outcome. Major progress has been made in the imaging of these vascular abnormalities. Magnetic resonance imaging (MRI) in particular has revolutionized the non-invasive and especially the non-irradiating exploration of many of them. It provides information about the extent of the lesion and allows an etiological approach in many cases. Moreover, neuroradiologic evaluation of vascular cerebromeningeal lesions benefits not only from the now-standard diagnostic neurologic imaging methods of CT and MRI, but also from various advances in the techniques of functional imaging. Accordingly, for Sturge-Weber syndrome, functional imaging provides hope for an early prognosis, in particular cognitive, when these techniques are more widely used (SPECT, PET, especially the new advanced sequences of perfusion in MRI-DTI). Chronic - indeed lifelong - coagulation abnormalities, with phases of aggravation, occur in approximately half of the patients with venous malformations of the trunk and limbs, and more rarely in neck and face sites. This is not without consequences, but also not without therapeutic solutions: screening for it is therefore essential (measurement of dimer and fibrinogen levels). The discovery of gene mutations at the origin of some familial vascular malformations provides complementary data for the current classification of vascular abnormalities. It suggests that targeted therapy may be possible but probably not for quite a bit longer.