This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Demyelinating disorder, Subject name: Medicine
A 50-year-old woman complains of clumsiness in her hands while working in the kitchen: She recently burned her hands on the stove without experiencing any pain. Neurologic examination reveals bilateral weakness of the shoulder girdles, arms, and hands as well as a loss of pain and temperature sensation covering the shoulder and upper limb in a cape-like distribution. Severe atrophy is present in the intrinsic muscles of the hands. The most likely diagnosis is: 
Select and explain. 
A. ALS, B. Subacute combined degeneration, C. Syringomyelia, D. Tabes dorsalis.
C: Syringomyelia
Answer: C: Syringomyelia 
Explanation: Syringomyelia: cavitation of the spinal cord seen in the cervicothoracic segments. This results in b/L loss of pain and temperature sensation in a cape-like distribution as well as wasting of the intrinsic muscles of the hands. Sensory deficit is directed from proximal to distal pas. ALS is a pure motor syndrome Subacute combined degeneration includes both sensory and motor deficits Werdnig-Hoffmann disease is a pure motor disease Tabes dorsalis is a pure sensory syndrome (neurosyphilis).