Leprosy in peripheral nerves: histopathological findings in 119 untreated patients in Nepal.

Abstract

The histopathology in 153 biopsies from 119 patients suffering from tuberculoid, borderline (dimorphous) or lepromatous leprosy, untreated at 1st presentation and diagnosis, is described. They included biopsies of skin, dartos muscle, nasal mucous membrane and nipple. Examination of serial sections by light microscopy revealed a density of cellular infiltration in non-lepromatous cases or of bacilli in macrophages and Schwann cells in lepromatous cases, which was marked in degree and usually widespread from one end of the biopsy to the other. Intraneural caseation was recorded in 4 patients with tuberculoid or borderline-tuberculoid leprosy and many others in this part of the spectrum showed extensive disruption of perineurial and endoneurial structure. In lepromatous patients the numbers of bacilli in the endoneurial area not infrequently exceeded 1000 per oil immersion field. Although well-known to histopathologists familiar with this disease, the significance of these findings in patients presenting for the 1st time is not well appreciated by those working in general medicine, neurology, epidemiology or in leprosy control.