A 27 year old man presents to a physician because he was not able to feel a burn that he had sustained on the stove burner. Neurologic studies demonstrate bilateral loss of pain and temperature sensation in the upper extremities with preservation of touch sensation. No motor abnormalities are observed. This patient's condition has been most frequently associated with which of the following?

The patient most probably has syringomyelia, in which softening and cavitation around the central canal of the spinal cord damages crossing fibers of the spinothalamic tract with resulting bilateral loss of pain and temperature (but not touch) sensation in the upper extremities. Many of the patients with syringomyelia have Arnold-Chiari malformation, in which there is a congenital protrusion of the cerebellum and medulla through the foramen magnum. Broca's aphasia is a nonfluent aphasia due to damage to the inferior frontal gyrus. Horner's syndrome is due to damage to the sympathetic innervation of the face, with resulting ptosis, miosis, and anhidrosis. Tabes dorsalis is a degeneration of the dorsal columns and dorsal roots of the spinal cord due to teiary syphilis, producing impaired proprioception and locomotor ataxia. Ref: Wyatt C., Butterwoh IV J.F., Moos P.J., Mackey D.C., Brown T.G. (2008). Chapter 11. Neuropathology. In C. Wyatt, J.F. Butterwoh IV, P.J. Moos, D.C. Mackey, T.G. Brown (Eds), Pathology: The Big Picture.