▁a ▁dis order ▁called ▁L UM B AR ▁synd rome . ▁Multiple ▁cut aneous ▁hem ang iom as ▁in ▁inf ants ▁may ▁be ▁an ▁indicator ▁for ▁li ver ▁hem ang iom as . ▁Screen ing ▁for ▁li ver ▁invol vement ▁is ▁often ▁recommended ▁in ▁inf ants ▁with ▁five ▁or ▁more ▁skin ▁hem ang iom as . ▁ ▁C aus es ▁The ▁cause ▁of ▁hem ang i oma ▁is ▁currently ▁unknown , ▁but ▁several ▁studies ▁have ▁suggested ▁the ▁importance ▁of ▁est ro gen ▁signal ing ▁in ▁pro l ifer ation . ▁ ▁Local ized ▁soft - t issue ▁hy po x ia ▁couple d ▁with ▁increased ▁circul ating ▁est ro gen ▁after ▁birth ▁may ▁be ▁the ▁stim ulus . ▁Also , ▁a ▁hypothesis ▁was ▁presented ▁by ▁research ers ▁that ▁mat ernal ▁pla cent a ▁em bol izes ▁to ▁the ▁f etal ▁der mis ▁during ▁gest ation , ▁resulting ▁in ▁hem ang iom agen esis . ▁However , ▁another ▁group ▁of ▁research ers ▁conducted ▁gen etic ▁anal ys es ▁of ▁single - n uc le ot ide ▁polym orphism ▁in ▁hem ang i oma ▁t issue ▁compared ▁to ▁the ▁mother ' s ▁DNA ▁that ▁contrad icted ▁this ▁hypothesis . ▁Other ▁studies ▁have ▁revealed ▁the ▁role ▁of ▁increased ▁ang i ogen esis ▁and ▁vas cul ogen esis ▁in ▁the ▁et i ology ▁of ▁hem ang iom as . ▁ ▁Di agn osis ▁ ▁The ▁majority ▁of ▁I H s ▁can ▁be ▁diagn osed ▁by ▁history ▁and ▁physical ▁exam ination . ▁In ▁rare ▁cases , ▁imag ing