What is "insular sclerosis"

Sclerosis \Scle*ro"sis\, n. [NL., fr. Gr. (??, fr. sklhro`s hard.]

1. (Med.) Induration; hardening; especially, that form of induration produced in an organ by increase of its interstitial connective tissue.

2. (Bot.) Hardening of the cell wall by lignification.

   Cerebro-spinal sclerosis (Med.), an affection in which patches of hardening, produced by increase of the neuroglia and atrophy of the true nerve tissue, are found scattered throughout the brain and spinal cord. It is associated with complete or partial paralysis, a peculiar jerking tremor of the muscles, headache, and vertigo, and is usually fatal. Formerly referred to as multiple sclerosis, disseminated sclerosis, or insular sclerosis, but now usually called only multiple sclerosis, or MS.