A healthy 1-month-old boy with lesions on his back that had been present since birth. He had no relevant family history. On examination he had pink plaques on his back with central bluish colouration and depression and some prominent ectatic vessels, surrounded by a dusky halo (image). The plaques were soft, poorly compressible, painless, and more prominent during crying. Musculoskeletal examination was normal, as were blood count, liver enzymes, renal function, and coagulation.
What’s the most likely diagnosis ?
