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Are Juvenile Hemangiomas Related to Maternal Placentas?

Juvenile hemangiomas, which occur in up to 10 percent of children, appear most commonly on the head and neck, grow rapidly within weeks after birth, and usually involute spontaneously. The nature of these tumors is not known. Given that they occur neonatally, their etiologic relation to maternal placental vessels has been questioned. In two studies, researchers investigated the pathogenesis of these entities.

Researchers from an Arkansas university-affiliated pediatric hospital examined juvenile hemangiomas, a control group of various other vascular neoplasms, and normal tissue samples for the presence of the placenta-associated vascular antigens FcRII, Lewis Y antigen, and GLUT1. Endothelial cells in 66 juvenile hemangiomas strongly expressed each of these markers, which were also strongly expressed by cells in the vessels of placental chorionic villi; no endothelial cells of the other vascular neoplasms expressed any of these markers. The authors hypothesize a relation between juvenile hemangiomas and the maternal placental microvasculature, proposing two possible mechanisms of origin for the hemangiomas: the colonization of mesenchyme by angioblasts that are aberrantly switched to a placental endothelial phenotype or the embolism of placental endothelial cells.

In a separate study, researchers in St. Louis investigated the possibility that placental trophoblasts are the cells of origin for juvenile hemangiomas. Cells from 12 infantile hemangiomas were analyzed using a panel of antibodies known to label placental trophoblasts, including human placental lactogen, placental alkaline phosphatase, and cytokeratins 7, 8, and 17. No cells were stained; these negative results suggest that juvenile hemangiomas are not closely related to placental trophoblastic cells.

Comment: Results from this pair of studies suggest a relation between maternal placenta and juvenile hemangiomas. It appears that the relation involves the microvasculature within the chorionic villi and not the trophoblasts. The exact mechanism by which juvenile hemangiomas occur in a minority of neonates while sparing the majority remains to be elucidated and will probably require functional studies based in part on the data gleaned from these morphologic examinations.

— BR Smoller

Published in Journal Watch Dermatology June 12, 2001

Citation(s):

North PE et al. A unique microvascular phenotype shared by juvenile hemangiomas and human placenta. Arch Dermatol 2001 May 137 559-570.

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Bree AF et al. Infantile hemangiomas: Speculation on placental trophoblastic origin. Arch Dermatol 2001 May 137 573-577.

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• Medline abstract (Free)