Ultrastructural changes of cutaneous nerves in scleroderma.

Ultrastructural changes in cutaneous nerves of 38 patients with progressive scleroderma and eight patients with circumscribed scleroderma are described in the present study. Changes in the myelinated as well as in the unmyelinated fibers were observed in all cases. Myelinated fibers exhibited progressive disintegration of their myelin sheaths. Edema of the cytoplasm and various lesions of the organelles were observed in the Schwann cells. The basal membranes of both myelinated and unmyelinated fibers were irregularly thickened and flimsy in appearance. The axis cylinders were affected to a lesser extent. Edema of the axoplasm, and, less often, reduction of the number of neurofibrils and microtubules were observed there. Sometimes, the nerve fibers were enwrapped compactly by a considerable amount of collagen fibrils. The observed changes of the peripheral skin nerves are very often secondary. They are the morphologic basis of a limited or generalized neuropathy which sometimes develops.