Acute enlargement of a vascular plaque and gait changes in a young girl

A 15 month old girl presented to the emergency department with a one week history of unsteady gait and approximately three to four unexplained falls each day. She had been walking independently and without difficulty since she was 12 months old. At birth, she had a broad pink patch on the right medial buttock, which had been diagnosed on clinical examination as a congenital haemangioma. The site had grown proportionally with the patient until these symptoms started, when this vascular stain became acutely indurated, and a contiguous, erythematous plaque appeared superiorly, overlying the sacrum. On examination, a swollen, violaceous, warm, subcutaneous plaque with superimposed telangiectases was noted overlaying the sacrum. This extended to the right buttock, where an accompanying pink-purple stain was present (fig 1). No thrills or pulsations were noted. Neurological examination showed no paralysis. Relevant laboratory findings are shown in table 1.