What Looms Beneath

Question: A 6 month old male is referred for treatment of a facial lesion. Examination reveals a port-wine stain in the V1 distribution. His mother notes that he has been treated for seizures since birth, and medicines are becoming less effective. What is the most likely diagnosis?

[Answer will be posted with next week's new question]

Answer to last week's question, "The Devil's In The Details" (July 9, 2018)

Vestibular schwannoma.