CPC12 Clinical relevance of biopsy in leprosy after World Health Organization multidrug therapy: an ambispective observational study

Abstract

Despite being eliminated as a public health problem, leprosy continues to present therapeutic challenges. Persistence of residual lesions and bacilli after multidrug therapy (MDT) creates uncertainty regarding true disease activity, and there is limited evidence on the role and relevance of histopathology in treated cases. Our aim was to compare the histopathological changes in patients with leprosy before and after completion of MDT and to identify salient histopathological features at both timepoints. The study was conducted at a tertiary care centre over a period of 24 months. In total 52 patients were included, comprising cases of paucibacillary (PB) and multibacillary (MB) leprosy. Clinical findings, slit-skin smear (SSS) results, histopathology and Fite staining were analysed both before and after treatment. Biopsies were assessed for granuloma fraction, bacillary index of granuloma, nature of inflammatory infiltrate, and dermal and epidermal changes. Clinicohistopathological concordance was observed in 3% of cases (43 of 52). Residual post-treatment lesions were noted in 54% of patients with PB and 14% of patients with MB. On biopsy, complete resolution of granuloma was seen in 69% of cases of PB and 28.5% of cases of MB. Cases of both PB and MB showed statistically significant decreases in the granuloma fraction, with P-values of 0.001 and 0.04, respectively. Patients with post-treatment live bacilli on SSS did not have a significant decrease in granuloma fraction and had chronic erythema nodosum leprosum (ENL) during the course of treatment. Features such as dermal fibrosis, fibromyxoid changes, increased basal pigmentation and mast cell infiltrates were statistically significant in post-treatment cases. Fite stain was more sensitive than SSS, with P-value of 0.01. Features such as dermal fibrosis, fibromyxoid changes, decrease in granulation fraction and increased basal pigmentation signify treated cases. Chronic ENL, prolonged steroid use and post-treatment increase in granuloma fraction are associated with persistence of live bacilli, suggesting the need for prolonged treatment. Long-term studies are needed to correlate histopathology findings with the risk of relapse.