A 3-month-old girl was referred to our Vascular Anomalies Center for assessment of a rapidly enlarging left hand mass. Although present at birth as a mild localized swelling, significant growth was not noted until approximately 6 weeks of age. The infant's medical, surgical, and family history were unremarkable, and she was initially evaluated by her pediatrician, who suspected a vascular tumor or malformation.
Physical examination revealed a solitary, 2.5 × 3 × 2.5-cm, firm, nonmobile, subcutaneous nodule with slight erythematous to blue hue and overlying telangiectasia protruding from the left hypothenar region (Figure 1). A handheld Doppler device detected fast blood flow at the periphery. There were no other skin abnormalities.