Epidemiology

 sporadic or familial (autosomal dominant with reduced penetrance)
 usually occurs in children younger than 5 years
 may occur in adults (also in pregnancy)

Localization:

 restricted to skin (neck, shoulders, or trunk)

Macroscopy

 exophytic, red lesion

Microscopy

 'cannonball' distribution of capillary-sized vessels in the dermis
 vessels may form rounded nodules ('tufts')
 lymphatic vessels present at the periphery of lesion

Evolution

 slow, progressive growth, then stable
 may regress