12th May 2024

A 54-year-old man presents with progressive weakness on the left side of his body, slurred speech, and episodes of confusion.

A 54-year-old man presents with progressive weakness on the left side of his body, slurred speech, and episodes of confusion. He has a history of melanoma treated two years ago. A CT scan of the brain reveals multiple hyperdense lesions in the right parietal lobe and the cerebellum. Biopsy of one of the lesions confirms metastatic melanoma.

Which is the most likely route by which this tumour spread to the brain?