A 47-year-old man comes to the physician for a 2-month history of progressively worsening back pain, leg weakness, and difficulty walking. Physical examination shows decreased muscle strength in the lower extremities bilaterally and a Babinski sign on the left. Sensation is reduced in a band-like distribution across the thoracic region. MRI shows a thoracic spinal mass. Which of the following is the most likely diagnosis?
Ependymoma
Meningioma
Pilocytic astrocytoma
Schwannoma
Syringomyelia
