A rare disease affecting the SPINAL CORD, in which irregular cavities form, surrounded by an excessive amount of the connective tissue of the central nervous system. These cavities encroach upon the nerve-tracts in the cord, producing loss of the sense of pain or of that for heat and cold in parts of the limbs, although the sensation of touch is retained. Another occasional symptom is wasting of certain muscles in the limbs. Changes affecting outlying parts like the fingers are also found. Because of their insensitiveness to pain, these are often burnt or injured; troublesome ulcers, or loss of parts of the fingers, may result. The condition of the spinal cord is probably present at birth, although the symptoms do not usually appear until adulthood. The disease is slowly progressive, although sudden exacerbations may occur after a cough, a sneeze, or sudden straining.