MRCP2-3054

MRCP2-3054

A 55-year-old woman presents with a persistent headache that has lasted for 4 months. She recently experienced a discharge from her left ear, which was diagnosed as Aspergillus fumigatus and treated with eardrops. However, she now reports double vision and sciatic pain in her left leg. She has a history of breast cancer and is currently taking Tamoxifen. On examination, she has bilateral papilloedema, paretic lateral recti, and a mild facial paresis on the left side. Her ankle jerk is hypoactive and planters are flexors on both sides. Further investigations reveal scattered leptomeningeal enhancement on an MRI brain scan and elevated levels of ALT and ESR. The CSF analysis shows elevated protein and lymphocytes, but no malignant cells or evidence of infection. What is the most likely diagnosis?