Endoneurial proliferation of perineurial cells in leprosy.

In leprous neuropathy the perineurium has very often an abnormal multilayered appearance and is infiltrated by many different types of inflammatory cells. We report here 13 cases characterized by an abnormal endoneurial proliferation of fibroblasts which seems to differentiate in perineurial cells. In several instances there is formation of many intrafascicular microcompartments. Such aspects have been described in various, but infrequent, cases of experimental and human neuropathies. It seems that severe Wallerian degeneration, diffuse endoneurial macrophage infiltration and lesion of the perineurium might lead to such a process.