STUDY ON THE ULTRASTRUCTURE AND ACETYLCHOLINESTERASE ACTIVITY IN VON RECKLINGHAUSEN'S NEUROFIBROMATOSIS

Abstract

The cutaneous nodules obtained from 7 patients with von Recklinghausen''s neurofibromatosis were investigated by EM; ultrastructural localization of acetylcholinesterase activity was demonstrated in the nerve fibers of this tumor for the first time using Karnovsky''s thiocholine method. The enzymatic activity was mainly found in unmyelinated fibers, exactly associated with their axonal membranes, the interspace between the apposing axonal and Schwann cell membrane and some different mesaxons, which indicated their cholinergic nature. Almost all myelinated fibers and some unmyelinated fibers did not possess the activity. The relationship between axon and Schwann cell was quite similar to that of normal peripheral nervous system but 2 striking alterations of the nerves existed: the dissociation of unmyelinated fibers, and the degenerative changes of the axon and the myelin sheath. As evidence of schwannian proliferation, onion bulb formations and collagen pockets were observed. Some signs of fibroblastic proliferation were also found. The probable histogenesis of this disease was discussed.