Hemangiomas and Spitz Nevi
A. Howland Hartley MD1
James E. Rasmussen MD2
1 Professor of Dermatology and Pediatrics, Dept of Dermatology, The University of Michigan, Ann Arbor
2 Private practitioner
Hemangiomas are, with the exception of warts, the most common benign tumors found in infants and children. A great many lesions are in this general category. The three most common types are capillary (strawberry) hemangiomas, cavernous hemangiomas, and port wine stains. In the majority of patients, these lesions cause no significant morbidity or mortality. Important exceptions to this general rule will be highlighted.
GENERAL CONSIDERATIONS
Hemangiomas are benign blood vessel tumors with a greatly variable capacity for growth and involution. Histologically, strawberry hemangiomas are proliferations of endothelial cells with small capillary-sized lumina. Cavernous lesions have larger, more mature vessels. Proliferation of endothehial cells is absent in port wine stains, in which dilated, thin-walled, mature capillaries are found in the upper and lower dermis.
The origin of congenital vascular lesions in unknown. The question remains whether hemangiomas are true congenital benign neoplasms or hamartomas of primitive mesenchymal tissue. The factors responsible for growth and involution of hemangiomas are also unknown. Mast cells, found in abundance in actively enlarging lesions, may play an important role. With the exception of a few rare syndromes, there is no known genetic inheritance os hemangiomas, although familial cases have been reported in as many as 10% of patients.
