30th September 2021

A 56-year-old male presents to the emergency department with new-onset headache

A 56-year-old male presents to the emergency department with new-onset headache, confusion, and personality changes. His husband reports that he has a long-standing history of HIV, for which he sees a specialist, though he has previously been relatively well. The family history includes vascular dementia. Of note on examination, the patient demonstrates right-sided weakness of both limbs. A contrast CT scan of the head is requested urgently, which reveals multiple ring-enhancing lesions.

Which of the following is the most likely underlying diagnosis?

Select the SINGLE most appropriate option from the list below. Select ONE option only.