|Year : 2013 | Volume
| Issue : 2 | Page : 68-73
Histomorphological study of leprosy
Veena Shivamurthy1, Hurukadli Gurubasavaraj2, Pattabhirama Sastry Shashikala3, Prakash Kumar2
1 Assistant Professor, Department of Pathology, SIMS, Shimoga, India
2 Department of Pathology, JJMMC, Davangere, Karnataka, India
3 Department of Pathology, SSIMSRC, Davangere, Karnataka, India
|Date of Web Publication||20-Jun-2014|
Department of Pathology, SIMS, Shimoga - 577 201, Karnataka
Source of Support: None, Conflict of Interest: None
Context: Leprosy still continues to be an important public health problem. Aims: The present study was undertaken to study the histopathological features of leprosy in skin biopsies and to categorize them into various types based on microscopy, bacterial index of granuloma and to correlate with clinical presentations whenever possible. Materials and Methods: Skin biopsies after adequate fixation in 10% of formalin, were routinely processed and paraffin embedded sections of 5 μ thickness were stained with H and E and fite -faraco stain and were studied microscopically. Results: A total of 200 skin biopsies were obtained from patients with an age range of 7 -85 years, majority were in 3 rd decade, with male to female ratio of 2.6:1. Borderline tuberculoid was the most common type of leprosy (72.5%). Most common clinical feature was loss of sensation. Atrophic epidermis and grenz zone was more common in lepromatous leprosy and borderline leprosy. There were 6 biopsies with lepra reaction, 4 (66.6%) were of type 1 and 2 (33.3%) were of type 2 reactions. Majority of biopsies were of paucibacillary type (77%) and rest (23%) were of multibacillary type, clinicopathological correlation was observed in 150 biopsies (75%). Conclusions: For accurate diagnosis, correlation of clinical and histopathological features along with bacterial index appears to be more useful than considering any of the single parameters alone.
Keywords: Bacterial index of granuloma, histomorphology, leprosy
|How to cite this article:|
Shivamurthy V, Gurubasavaraj H, Shashikala PS, Kumar P. Histomorphological study of leprosy. Afr J Med Health Sci 2013;12:68-73
|How to cite this URL:|
Shivamurthy V, Gurubasavaraj H, Shashikala PS, Kumar P. Histomorphological study of leprosy. Afr J Med Health Sci [serial online] 2013 [cited 2019 Jan 19];12:68-73. Available from: http://www.ajmhs.org/text.asp?2013/12/2/68/134893
| Introduction|| |
Leprosy is one of the leading causes of physical disabilities, which contribute to intense social stigma resulting in discrimination of patients and their families.
Leprosy is a chronic infectious disease caused by Mycobacterium leprae, principally affecting the cooler parts of the body, mainly skin and peripheral nerves; it also involves muscles, eyes, bones, testis and internal organs.  Leprosy is known, since ancient times as "Kushtaroga." The causative agent of leprosy, M. leprae, was discovered in 1873 by Armauer Hansen. Even though, it was discovered early, it has not been cultured as yet.  Leprosy is an important public health problem in most of the developing countries. Hence control of communicable disease is based on identifying and destroying or attacking the causative organism. 
The clinical manifestations of leprosy are so varied and diverse and can mimic a variety of unrelated diseases. Presentation may vary from an insignificant skin lesion to extensive disease causing profound disability/deformities. 
Histopathological study of leprosy is very important in understanding the disease, its varied manifestation and complications. Hence clinicopathological correlation is extremely important in patient care and management.
Since exact typing of leprosy is sometimes clinically not possible, added to this the poor results obtained by slit skin smear will lead to false negative diagnosis. To prevent this, histopathological examination should be done in all suspected cases.
This study was undertaken to know the histopathological features of leprosy in skin biopsies. To categorize these into various types based on microscopy, bacterial index of granuloma. And to correlate with clinical presentations whenever possible.
| Materials and Methods|| |
The present study (prospective study) on histomorphological analysis of skin biopsies in leprosy was undertaken in Department of Pathology, J.J.M. Medical College, Davangere, over a period of two years from June 2006 to June 2008.
Materials for the study consisted of skin biopsies obtained from patients clinically diagnosed with leprosy who attended either Out -patient Department of leprosy clinics of Chigateri District Hospital and Bapuji Hospitals that are attached to J.J.M. Medical College, Davangere.
Skin biopsies were obtained by incisional biopsy performed by the Dermatologist and were sent to the Department of Pathology in 10% of formalin. After adequate fixation for about 8 -12 hours, the biopsies were submitted for routine processing, following which the paraffin embedded sections of 5 μ thickness were stained with Hematoxylin and Eosin (H and E) for morphological analysis and Wade Fite staining , for identifying the bacilli.
The procedure followed for Fite Faraco Stain was Wade -Fite method for M. leprae in paraffin section (modified from Klade, 1957). 
The procedure was slightly modified in the present study.
Coconut oil instead of peanut oil and 5% of sulfuric acid instead of 1% acid alcohol were used.
The sections were observed under oil immersion using ×100 objectives. The bacillary index (BI) was assessed in exactly the same way as the one followed for smear. The entire dermis was observed to assess the logarithmic index of bacilli.
Following was the scale used to calculate the BI. 
1+ = 1 -10 bacilli in 100 oil immersion field (OIF) - examine 100 OIF
2+ = 1 -10 bacilli in 10 OIF - examine 100 OIF
3+ = 1 -10 bacilli in 1 OIF - examine 25 OIF
4+ = 10 -100 bacilli in 1 OIF - examine 25 OIF
5+ = 100 -1000 bacilli in 1 OIF - examine 25 OIF
6+ ≥ 1000 bacilli in 1 OIF - examine 25 OIF.
H and E stained sections were studied to observe the various changes that occurred in the epidermis, papillary, reticular, deep dermis, neurovascular bundles and adenexa.
Diagnoses were made based on histopathology and bacterial index of granuloma (BIG) and were classified according to Ridley and Jopling classification.
| Results|| |
The present study included 200 skin biopsies from patients who were clinically diagnosed with leprosy.
Among the 200 biopsies, 145 (72.5%) were of borderline tuberculoid (BT) type, 21 (10.5%) were borderline lepromatous (BL) type, 15 (7.5%) were indeterminate leprosy (IL), 11 (5.5%) were lepromatous leprosy (LL), 5 (2.5%) were borderline (BB) and 3 (1.5%) were of tuberculoid leprosy (TT) [[Table 1] and [Figure 1] and [Figure 2]. Patient's age ranged from 7 years to 85 years. Among them majority - 56 (28%) of the patients were in 3 rd decade.
|Figure 1: Microscopic images of tuberculoid leprosy and borderline tuberculoid|
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There were 145 (72.5%) male patients and 55 (27.5%) female patients, with male to female ratio (M:F) of 2.6:1. 185 (92.5%) had clinical feature suggestive of anaesthesia (loss of sensation), 147 (73.5%) were having nerve thickening, 137 (68.5%) had hypo pigmented skin lesions, 60 (30%) had erythematous skin lesions [Figure 3], 29 (14.5%) had a combination of lesions, 9 (4.5%) had nodules, 3 (1.5%) of them had tropic ulcer [Graph 1].
These were the various epidermal changes observed [Table 2]. In 157 (78.5%) the epidermis was unremarkable, in 43 (21.5%) the epidermis was atrophic, 11 (5.5%) biopsies showed mild basement membrane erosion and 3 (1.5%) showed surface ulceration.
Among 200 biopsies 154 (77%) were paucibacillary (PB), 46 (23%) were multibacillary (MB) [Table 3].
Among 6 biopsies of lepra reaction [Table 4], 2 (33.33%) were diagnosed with BT type 1 reaction upgrading, in that 1 (16.66%) biopsy showed BI of 1+. Other 1 (16.6%) was diagnosed with BT type 1 reaction down grading, which showed BI of 3+. 1 (16.6%) biopsy was diagnosed with LL with features of type 1 reaction, which showed BI of 5+. Two biopsies (33.33%) one each showed features of LL and BL with type 2 (erythema nodosum leprosum) reaction [Figure 4] and [Figure 5], among which 1 (16.66%) biopsy showed BI of 4+ and the other 1 (16.66%) showed BI of 6+.
Of the 138 clinically diagnosed BT cases, 123 (89.1%) were of BT type, 2 (1.44%) were of TT type, 1 (0.72%) was BB, 2 (1.44%) were BL, 1 (0.72%) was LL, 9 (6.52%) were of IL type.
|Figure 3: Clinical photos of borderline tuberculoid and borderline borderline|
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|Figure 4: Lepromatous leprosy - erythema nodosum leprosum, bacillary index 6+, acid-fast bacilli in endothelium and in subepidermis|
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|Figure 5: Lepromatous leprosy — erythema nodosum leprosum showing|
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Of the 4 clinically diagnosed BB cases, 2 (50%) were of BT type and 2 (50%) were of BB type.
Of the 37 clinically diagnosed BL cases, 17 (45.94%) were of BT type, 2 (5.40%) were of BB type, 13 (35.13%) were of BL type, 2 (5.40%) were of LL type, 3 (8.10%) were of IL type.
Of the 16 clinically diagnosed LL cases, 2 (12.5%) were of BT type, 6 (37.5%) were of BL type, 8 (50%) were of LL type.
Of the 3 clinically diagnosed IL cases, 3 (100%) were of IL type.
| Discussion|| |
Leprosy or Hansen's disease is a slowly progressive infection caused by M. leprae affecting the skin and peripheral nerves. It is exclusively a disease of human and only source of infection is a leprosy patient. Leprosy still continues to be an important public health problem.
Accurate diagnosis is of fundamental importance to all aspects of leprosy epidemiology, management and prevention of disability. Under diagnosis will lead to continued transmission of disease and much needless sufferings.
Histopathological examination continues to be an important tool in accurate diagnosis and classification of leprosy and still remains the gold standard.
During the study period of two years, a total of 499 skin biopsies were received, among which 200 skin biopsies were of leprosy, which constituted (40.08%) of the total skin biopsies.
All the biopsies were from patients who were clinically diagnosed with as leprosy.
Disease occurrence in leprosy is often related to age at detection rather than age at the onset of disease. It is known to occur at all ages ranging from early infancy to very old age. 
The attitude of society, methods of case detection, type of personnel carrying out survey, method and frequency of examination, the criteria adopted for diagnosis, type of classification of disease, are some variables that affect the description of the condition. In general, leprosy is believed to be more common in males than in females. 
Male predominance may be because of many factors such as industrialization, urbanization and more opportunities for contact in males, social customs and taboos may account for the smaller number of females reporting for treatment to the hospital. 
There are several factors, which influence the sex predominance in the endemic areas. The main factors causing the sex difference is the opportunity for contact and practically no difference is noted when the opportunity for contact remains the same. 
The most commonly encountered type of leprosy was BT 145 biopsies (72.5%), second common type was BL 21 biopsies (10.5%), TT - 3 biopsies (1.5%) was the least encountered type.
Borderline group constituted the major spectrum 171 biopsies (85.5%), which included BT, BB, BL, similar to findings of other authors. ,,,,
A sizable portion of leprosy patients will be in a continuously changing immunological spectrum, i.e., BT, BB and BL. Hence majority of cases belong to borderline group. 
According to many observers features of both tuberculoid and LL can occur in a same section or in serial sections or in different lesions of the same borderline cases. Immunological instability in these borderline cases makes them move in either direction along the borderline spectrum. With treatment, they move towards tuberculoid pole or without treatment they tend to move towards lepromatous pole. If the disease is recognized at an earlier stage and biopsy is taken, it will be in BT stage or if the disease is recognized at a later stage, it may be in BL stage. 
Increased awareness of the people to leprosy because of many national programs makes them to present at an earlier stage to leprosy clinics, which may contribute to increased number of borderline group of leprosy.
Loss of sensation (anaesthesia) (92.5%) was the most common clinical feature, Nerve thickening (73.5%) was the 2 nd most common feature observed, common nerves affected were ulnar nerve, lateral popleteal nerve, radial nerve. Hypo pigmented skin lesion (68.5%) were the 3 rd common clinical feature observed. Trophic ulcer (1.5%) was rare clinical feature.
In most of the biopsies epidermis was unremarkable (78.5%), in rest the epidermis was atrophic (21.5%), ulceration (1.5%) was the rare histopathological feature observed.
Grenz zone was the most common feature observed in all the biopsies of LL (100%) and the majority of biopsies of BL (85.71%). It was very rare finding in BT (2.2%) and was absent in TT.
In the present study, majority of the patients were of PB type 154 (77%) and the rest were of MB type 46 (23%).
Type 1 reactions are associated with a change in the cell mediated immunity. 
Type 2 reactions are associated with immune complex deposition. 
In present study there were 6 (3%) biopsies, which showed features of lepra reaction.
Complete resolution and healing of a leprosy lesion is a slow process. In TT, BT, BB lesions the epithelioid cells do not undergo fatty change or any other sort of regressive change. On treatment the morphology remains same as for active lesions. Eventually, the epithelioid cells disappear and the classification becomes indeterminate. With successful treatment, this should happen within a year or less. In BL, LL there will be mild foamy macrophages without large vacuoles, lymphocytes are present. 
Relapsing leprosy was considered when there was return of the disease after its apparent cessation. The end point of cure is recognized by the disappearance of M. leprae in MB patients and by the complete resolution of granuloma in PB patients. 
In the present study, there were 32 (16.5%) patients who were on treatment or completed the treatment. Of these, 24 biopsies (75%) showed one or more features of resolving leprosy of BT type and the rest 8 biopsies (25%) showed features of relapse. Among relapsing type, majority 6 (75%) were of BT type and 1 (12.5%) each was of BL and LL type.
All the 24 biopsies, which showed resolving type, were from patients, who were on treatment and the 8 patients who had relapse had taken complete treatment, but the treatment was irregular.
Ideally to diagnose resolving or relapsing leprosy, features of previous biopsy should be considered. Since in the present study reports of previous biopsy or slides were not available, diagnosis was considered by comparing the present features with the details furnished by the dermatologist.
| Conclusion and Summary|| |
? Most of the patients affected were in the age range of 7 -85 years, male to female ratio of 2.6:1. BT type was the commonest type of leprosy. Most common features were loss of sensation (anaesthesia). Grenz zone was present in all 11 biopsies of LL (100%), well -formed epithelioid granulomas were observed in all cases of TT. Lymphohistiocytic aggregates/ILL formed granulomas were seen around arrector pilorum, nerve bundles and appendages in BT type. Therefore, biopsies from BL and LL showed diffuse macrophage aggregate with few lymphocytic infiltrate in BL type. There were six cases of lepra reaction, 4 (66.6%) were of type one reaction and 2 (33.3%) were type two reaction. PB type was more common and bacillary load increased as patients moved towards lepromatous pole. High BI of 5+ to 6+ was noted in LL type and low BI of 1+ was observed in BT type. TT and IL were negative for bacilli with BI -0.
As there can be some degree of overlapping among different types of leprosy both clinically and histopathologically, Correlation of clinical and histopathological features along with bacteriological index appears more useful for accurate typing of leprosy than considering any of the single parameters alone. This helps the clinician for better care and management of patients.
In depth studies are required to reassess the criteria, giving weight to different clinical signs and histopathological parameters. ,
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]
[Table 1], [Table 2], [Table 3], [Table 4]