Abstract :
Background: S-100 immunohistochemical staining may detect nerve involvement in early stages of tuberculoid spectrum of leprosy. This study investigated the use of S-100 in early diagnosis of the tuberculoid and borderline tuberculoid leprosy and compared its sensitivity with hematoxylin and eosin (HE) stains in discerning the nerve involvement.
Aims: To study the different histopathological patterns of nerve involvement in tuberculoid and borderline tuberculoid leprosy on S-100 immunostaining and also to compare the sensitivity of HE stain with S-100 immunostain in discerning the nerve involvement in these cases.
Materials and Methods: This was a descriptive, prospective and retrospective analytical study, which included patients with tuberculoid spectrum of leprosy. Histopathological examination (HPE) and immunohistochemical (IHC) analysis were performed on all skin biopsies using HE stain and S-100 immunostain, respectively. Then the sensitivities of both the stains in discerning the nerve involvement were calculated and the data was analyzed using SPSS software version 22 by applying chi-square test.
Results: The study included a total of 58 patients [tuberculoid (n=28), borderline tuberculoid (n=30)]. The mean age was 43 yrs. The most common clinical manifestation was hypopigmented patches (n=40, 70%) with loss of sensation (n=39, 68.3%). HPE revealed 36 cases with well-defined granulomas, 22 cases with ill-defined granulomas and 41 cases with nerve destruction. IHC analysis showed four different patterns of nerve damage (fragmented, n=32; infiltrated and fragmented, n=14; infiltrated, n=10; intact, infiltrated and fragmented; n=1). The sensitivity and positive predictive value (PPV) of HE staining in delineating the nerve involvement were 68.96% and 100%, respectively. Whereas, the sensitivity and PPV of S-100 IHC were 100% each.
Limitations: Less number of cases.
Conclusion: Use of S-100 IHC along with HPE aids in early, accurate and confirmatory diagnosis.
Keyword :
Tuberculoid leprosy, Borderline tuberculoid leprosy, S-100 immunostaining.