A nodular growth within a congenital birthmark

A 7-year-old Caucasian boy presented with a plaque on his right lower leg that was present at birth and had subsequently grown proportionally to the patient's overall growth, with no periods of rapid enlargement. The plaque would intermittently swell with prolonged physical activity, but the child denied associated pain, pruritus, or bleeding. Additionally, the child and his parents noted a small growth on the surface that developed six months prior to presentation. Examination showed a 3.5 cm uniformly erythematous plaque with a faint rim of pallor, along with two smaller satellite lesions (Figure 1). On the inferior aspect of the plaque was a 0.5 cm pink, well-circumscribed, smooth papule. On ultrasound, the plaque demonstrated high flow physiology with prominent underlying vessels. A shave biopsy of the papule was performed (Figure 2).