Comparison of two systems of classification of leprosy based on clinicopathological correlation

Aim and Objectives: To classify leprosy patients into multibacillary and paucibacillary types based on the number of body areas involved. To correlate histological diagnosis of skin biopsies of leprosy cases with clinical diagnosis using Ridley & Jopling classification. Material and Methods: The study group consisted of all clinical types of leprosy patients attending the dermatology OPD of MB Hospital, Udaipur during the study period 2011-2014. Complete dermatological examination was carried out in all the patients and the number of skin lesions were charted out. Body surface area was divided into 7 areas- Both upper limb 2 areas, both lower limbs 2 areas, anterior and posterior aspect of trunk 2 areas and head and neck 1 area. The number of involved area in each patient was counted and recorded. Each patient was given a score on a scale of 1-7 depending on the number of areas involved. Slit skin smear examination was performed in each patient. Skin biopsies were taken from the active lesions in all the leprosy patients and processed at department of pathology at RNT Medical College, Udaipur. They were stained by H&E and modified fite stain and graded as per Ridley & Jopling classification (1966) into IL, TT, BT, BB, BL & LL. Observation and Results: The present study was conducted on 100 untreated cases of leprosy, of these 8 were diagnosed as TT, 5 as BT, 36 as BB, 8 as BL,22 as LL and 21 as IL histologically. Clinical spectrum of leprosy cases in the present study revealed maximum cases (60%) in borderline group (BT+BB+BL), followed by LL (21%), TT (10%) and least in IL group (9%). In our study, out of 100 patients 59 showed positive SSS examination. 100% patients of LL & BL groups showed positivity while 100% patients of TT group showed negative results. In BB leprosy 72.2% patients were showed positive results. Only one patient (20%) showed positive SSS examination in BT group. Most of the patients with negative results belonged to IL group (46.34%). In the present study 41% of patients belonged to group with 1-5 skin lesions. 100% of clinically diagnosed TT, BT & IL cases come under the category of 1-5 lesions, while clinicohistopathological concordance was seen in 8/10 (80%) cases of TT and 5/20 (25%) cases of BT. 59 patients presented with more than 5 skin lesions, 100% clinically diagnosed cases of LL were confirmed histologically while one more case was detected on biopsy examination which was missed clinically. There were 14 cases of BB which presented with >5 lesions but histologically 27 cases were diagnosed. Only 7/24 cases were confirmed histologically with >5 lesions as BL. Conclusion: A specific sub-typing of Leprosy can be done by histopathological examination. Histopathology provides confirmatory information for suspect cases which can be missed in clinical practice or epidemiological studies. Clinical diagnosis highly sensitive and specific in case of polar groups of leprosy. For the exact sub typing of borderline cases, clinical diagnosis holds a lower sensitivity and specificity. Our findings suggest that patients with involvement of 2 or less body areas can be classified as PB leprosy and those with more than 2 body areas involved can be classified as MB leprosy for the purposes of therapy. There is only a fair agreement between clinical and histopathological approaches.