A 4-month-old boy is brought in by his mother for evaluation of a “birthmark” that has become more prominent with time. The child complains a bit when the lesion is touched.
His mother gives a history of a normal full-term pregnancy, with an uneventful delivery. Other than the skin lesion, there have been no other known problems with the child’s health.
EXAMINATION
The lesion in question is a 2-cm bright red nodule in the middle of the child’s forehead. There is a faint blue halo around it, but no other abnormalities are seen in the area or elsewhere on the child’s body. The patient otherwise appears well developed and well nourished; he is quite alert and reactive to verbal stimuli.
What is the diagnosis?