Neural pathology in leprosy during treatment and surveillance

The histological findings of 22 patients with neuritis, 14 developing pain, tenderness and swelling during treatment and 8 during surveillance are presented in this study. Seven patients' biopsies showed macrophage type and 14 had epithelioid cell type of granulomas. All biopsies showed evidence of active disease, except for two patients with macrophage granulomas where some regressive changes were evident. One biopsy showed fibrosis with lymphocytic infiltration. The histology of epithelioid cell granulomas had varied histopathological presentations ranging from non-reacting BT to those with severe type I reaction with caseation necrosis, liquefaction and calcification. Two macrophage granulomas showed partial regression though there was neuritis clinically and features of ENL in the biopsy sections. One biopsy showed histoid changes. All the biopsies showed similar histopathological features irrespective of whether neuritis appeared during treatment or surveillance. The features of reaction were severe in nerves, probably due to the adjuvant nature of lipid and myelin in the nerve tissue. The histopathological features of nerve biopsies from patients under surveillance appeared to be ongoing active disease rather than relapse.