Angiomas



Angiomas


Kristen Renee Aguirre

Macrene Alexiades

John Stuart Nelson




OVERVIEW

The presence of vascular tumors or proliferations in the skin is a common reason for patients to seek cosmetic or medical treatment. There is a large number of vascular tumors with wide-ranging clinical presentations and clinical behavior. The most common vascular tumors for which treatment is sought will be discussed in this chapter with discussion of the clinical interventions that should be taken. Table 3.3.1 provides a summary of recommended treatments for the various vascular disorders.


INFANTILE HEMANGIOMA


BACKGROUND

Infantile hemangiomas (IHs) are defined as vascular tumors or proliferations presenting at or near birth, which proliferate rapidly over the first year of life and then spontaneously involute.1,2,3 IHs are an anomalous localized proliferation of vasculature which are generally thought to arise sporadically, although up to 10% can be familial. These lesions are seen in 4% to 5% of infants, more commonly in girls (2-5:1), premature, low-birth-weight infants, as well as in multiple births, and in the setting of maternal amniotic sampling.3,4,5,6,7 Synonyms include benign infantile hemangioendothelioma, cellular hemangioma of infancy, juvenile hemangioma, and strawberry nevus.


PRESENTATION

IHs present as vascular tumors or proliferations presenting at or near birth; they proliferate rapidly over the first year of life and then spontaneously involute. The lesions may initially present as a cluster of telangiectasias with a halo of pallor, erythematous macules, bruise-like patches, or even areas of ulceration on the lips or perineum.8,9



PATHOGENESIS

There are several proposed mechanisms for the etiology of IHs, including somatic mutations in genes involved in vascular endothelial growth factor signaling
(VEGF receptors), as well as the genes involved in vascular development (eg, dual specificity phosphatase 5 [DUSP5]), which leads to clonal expansion of endothelial cells. Germline mutations have been found in familial cases and include VEGFR2, TEM8, and mutations on 5q. The placental theory of IHs postulates that the immunohistochemical similarities between IH cells and placental cells (GLUT-1, FcγRII, and Lewis Y antigen expression specifically) infer that IHs are either placental in origin or undergo differentiation toward the placental microvascular phenotype. There is further evidence that the placenta or, possibly, chorioangiomas within the placenta secrete substances that prepare the hemangioma sites for implantation. The approximately 9-month growth phase followed by stabilization and involution also lends credence to this hypothesis. This metastatic niche theory could provide possible future avenues for prevention and therapy.16 Finally, there is discussion regarding the role of hypoxia in the etiology of these lesions. This is supported by their association with hypoxic placental changes, placental insufficiency, low birth weight, regional arterial insufficiency seen in PHACE(S) and LUMBAR syndromes, and retinopathy of prematurity (GLUT-1-positive neovascularization). Estrogen may also play a role as IHs show such a significant predilection for female infants.17,18

Jun 29, 2020 | Posted by in Dermatology | Comments Off on Angiomas

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