Test your diagnostic skills in our regular dermatology quiz. What is the cause of these asymptomatic linear lesions?
A 14-year-old boy presented with several asymptomatic linear lesions on his back (Figure). They were noticed recently by his mother when she was assisting him in hospital after an operation that required a general anaesthetic (open reduction of a fracture). The boy had previously been healthy. In the past year, his voice has broken and he has had a growth spurt, gaining 5 cm in height.