pediatric endothelial lesions

Vascular dysplasias (vascular malformations) and hemangiomas, which are endothelial lesions of childhood, may result in considerable morbidity because they can cause discomfort and functional impairment and have a negative affect on the patient’s appearance.

Although vascular malformations may initially appear very similar to hemangiomas, they have distinct clinical courses.

Infantile hemangiomas progress through 3 stages: proliferative, involuting, and involuted. The proliferative phase is characterized by clinical growth. Once hemangiomas reach their maximum size, they begin to regress or involute. Histologically, this stage is characterized by endothelial apoptosis. Finally, the involuted stage of the hemangioma occurs when the original lesion is replaced by a connective tissue remnant.

In contrast to infantile hemangiomas, vascular dysplasias do not involute but continue to enlarge as the patient grows. The molecular differences between hemangiomas, which involute, and vascular malformations, which do not involute, are not well understood.

The transcription factor WT1 is expressed in the endothelium of hemangiomas but not in vascular malformations. Defects in WT1 signaling may underlie the inability of malformation endothelial cells to undergo physiologic apoptosis and remodeling.

References

 Lawley LP, Cerimele F, Weiss SW, North P, Cohen C, Kozakewich HP, Mulliken JB, Arbiser JL. Expression of Wilms tumor 1 gene distinguishes vascular malformations from proliferative endothelial lesions. Arch Dermatol. 2005 Oct;141(10):1297-300. PMID: 16230568