Histopathological evaluation of inflammatory & hereditary demyelinating polyneuropathies

In view of therapeutic implications and problems in clinical diagnosis, this study sought to evaluate and identify histopathological features of acquired inflammatory demyelinating neuropathies and hereditary demyelinating neuropathies. Sural nerve biopsies from 41 patients of demyelinating neuropathies, diagnosed on the basis of accepted clinical criteria, were studied using routine histological staining and special stains for myelin and axons. Chronic inflammatory neuropathies differed from the acute ones in having more endoneurial connective tissue, less of subperineurial oedema and presence of axonal sprouting and occasional onion bulb formation. Acquired neuropathies differed from hereditary neuropathies in having a more localized involvement, endoneurial oedema and variable inflammatory cell infiltration, while in hereditary neuropathies Schwann cell proliferation was diffuse and relatively uniform. The frequency and degree of nerve thickening was more in hereditary neuropathy. Evidence of inflammation was not universal, both in the acute and the chronic inflammatory demyelinating neuropathies. Histopathological examination is essential as the clinical and electrophysiological features alone may not offer definitive diagnosis.