Histopathological study of cutaneous granulomatous lesions

Introduction: Cutaneous granulomatous lesions are very common encountered by pathologist and dermatologists. Granulomatous dermatoses can be seen in infectious as well as non-infectious conditions leading to chronic inflammation. Clinical features are overlapping, a confirmatory causative finding is essential for the management of patient as treatment varies greatly according to cause. Histopathology remains a gold standard for diagnosis as well as further subtyping of granulomatous inflammatory disorders of skin. Materials and Methods: A retrospective study of skin lesion biopsies performed for 2 years and 2 months, from November 2016 to January 2019. Clinical details were obtained from requisition forms and the cases of granulomatous lesions were diagnosed and subclassified with the help of H&E and special stains. Result: The study includes 70 cases. A predominance of male were found with M:F ratio of 1.3:1. 21 to 30 years of age group was the commonest for granulomatous lesions with 34.3% of cases. Infectious granulomatous dermatoses were far high than non-infectious ones. Leprosy remained the major etiology followed by tuberculosis of skin. Conclusion: Leprosy contribute the major cause of granulomatous dermatoses in this study. Histopathology is gold standard for diagnosis and subclassification of cutaneous granulomatous lesion with a proper history and clinical details. © 2019 Published by Innovative Publication. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by/4.0/)


Introduction
The granulomatous inflammatory disorders are distinct type of chronic inflammatory processes where there is distinctive presence of granulomas. Granulomas are formed by accumulation of epithelioid type histiocyte, inflammatory cells and multinucleated giant cells. 1 Firstly granulomatous term was used by Virchow to describe a granule like tumor mass of granulation tissue. 2 Granulomatous inflammation is classified as type IV hypersensitivity reaction and can be induced by various kinds of infections, autoimmune, toxic, allergic and neoplastic conditions. Different types are granulomatous inflammatory lesion of skin are seen in different geographic locations. 3,4 A single etiology can produce varied histological features and conversely many granulomatous skin lesion with almost similar histological features can have different etiologies. 5 So cutaneous granulomatous lesion often present as a diagnostic challenge to pathologists and dermatologists. Granulomatous dermatoses due to infectious causes are very common and leprosy and tuberculosis are the leading etiologies. 6 Histopathology with routine and special stains play important role in identifying the specific infectious agent 1 and in classification of Hansen disease. 7,8 This study was conducted with the aim to evaluate the frequency and patterns of different cutaneous granulomatous lesions with its clinico-histopathological correlation to reach etiological diagnosis. Skin lesions having granuloma formation histopathologically were involved in the study. Cases without any granuloma formation and inadequate biopsies were excluded. Cases of cutaneous granulomatous lesion were studied on the basis of their histopathological and clinical findings.

Results
Among 70 cases were studied in which male predominance was noted with 40(57%) cases and females constituted 30(43%) case providing M :F ratio of 1.3:1. Most of the patients were noted in age group of 21 to 30 years i.e 24(34.3%) cases followed by 15(21.43%) case in 31 to 40 years. 82% of cases were seen below 50 years of age in our study.
Infectious granulomatous dermatoses were very common, only one case of sarcoidosis was found. Most cases of infectious dermatoses were noted in 21 to 30 years comprising 24(34.3%) cases. Leprosy remained the significant causative reason for infectious granulomatous dermatoses succeeded by tuberculosis of skin.

Discussion
Granuloma formation is due to type IV hypersensitivity reaction elicited by infectious and non infectious antigen. Granulomatous dermatoses are common in North India with overlapping clinical presentations. So, it becomes important to catch the definitive etiological diagnosis for their treatment. 9 Histopathology plays a pivotal role for confirmatory diagnosis like in several diseases of other system of the body. 6 The distribution of granulomatous dematoses varies widely according to geographic location. Very less number of studies done on the infectious granulomatous dermatoses, showing broad statistical variation for several lesions.
This study is comparable to Gautam et al, 7 Pawale et al, 10  Infectious granulomatous dermatoses were commonest in this study which is similar with the study by Bal et al. 12,13 Common est site of the skin lesions was upper extremity which is comparable with the study done by Gautam  In our study the commonest subtype of leprosy was found to be borderline tuberculoid 16 Granulomatous infiltration of nerve bundle, arrector pili muscle and adnexa along with proper clinical findings were helpful in the diagnosis of tuberculoid and borderline tuberculoid leprosy.
Cutaneous tuberculosis was the second commonest granulo matous dermatoses in this study, 2(2.86%) cases were diagnosed as lupus vulgaris were found to be negative on Ziehl Neelsen stain. Bal et al 12 found 5% positivity Z-N staining in cases of Lupus vulgaris. Z-N staining is specific for acid fast bacilli, still its positivity is low and varies with different studies. The present study did not revealed any case of cutaneous leishmaniasis. Rubina et al 13 found 56.7% cases in Pakistan. In this study one case was reported as cutaneous sarcoidosis based on epithelioid cell granuloma without caseastion and presence of inflammatory cells or Langhans giant cells. In this study there was 1 (1.43%) case of sarcoidosis somewhat similar to reported by Gautam et al 7 1.88%.

Conclusion
Etiology of granulomatous dermatoses varies greatly according to geographic distribution. Infectious form of granulomatous dermatoses are important causes with leprosy as the commonest etiology. Clinically granulomatous skin lesions have overlapping presentations. Histopathology plays a pivtol role in the diagnosis and sub-classification of cutaneous granulomatous lesion, along with the proper history and relevant clinical examination. Special stains play supportive role.
Our study reports the various important chronic granulomatous inflammatory dermatoses in this region of North India, which will be beneficial for management and implicating the health programmes.