A child with a bluish-purple discoloration on the chin

A 12-year-old previously healthy boy was referred to the paediatrician with a discoloration in the face. There was no apparent previous trauma. Some months ago, he had developed a discoloration on exactly the same place. Examination revealed a circumscribed, bluish-purple, non-tender, discoloration on the chin ( fig. 1A,B ). Due to recurrent mild iron deficiency, the differential diagnosis included cavernous haemangioma; the patient was therefore referred by the dermatologist for further work-up of...