CHIASMAL SYNDROME PRODUCED BY CHRONIC LOCAL ARACHNOIDITIS

As chronic local arachnoiditis has been regarded by some as a questionable condition, and has been suspected of being secondary to an adjacent tumor, we are reporting eight cases, three of which came to necropsy, to aid in counteracting this impression. The differential diagnosis was extremely difficult in some of the cases, but the postoperative visual improvement was sufficient to justify surgical procedures as a routine. Inflammatory lesions about the chiasm have been termed prechiasmal cisternal arachnoiditis,1chronic local arachnoiditis2and circumscribed arachnoid inflammation of the chiasm.3 CHIASMAL GROUP The ocular syndromes produced by lesions at or near the optic chiasm have been well classified by Cushing,4who enumerated seven possible causes : (1) meningiomas with a parasellar, rather than a suprasellar, point of origin; (2) pituitary adenomas; (3) congenital tumors arising from the craniopharyngeal pouch; (4) gliomas arising from the chiasm or the third ventricle;