Granulomatous skin lesions constitute a wide spectrum of diseases seen in the dermatology clinics and pose a great diagnostic dilemma for both the treating dermatologists as well as the diagnosing histopatho- logists. Cutaneous granulomas represent a mixed blend of disorders characterized by an inflammatory reaction in the skin, stimulated by a wide variety of factors including infections, foreign bodies, malignancies, metabolites, or certain chemicals[1].

The distribution of granuloma varies widely with the geographical location and depends on several factors, including the climatic variations, socio-economic status, cultural variations, educational status, and availability of

healthcare facilities[2, 3]. 

A cross-sectional prospective study was carried out in the Department of Pathology of a medical institute over a period of one year. The clinical findings and relevant information was recorded from patients using proper patient requisition forms.

Punch biopsies, including a small portion of adjacent normal skin were obtained and fixed in 10% neutral buffered formalin, grossed, processed by standard techniques, and stained with H&E stain. All the biopsies were examined microscopically, and those showing granulomatous pathology were included in this study.

Special stains such as modified Ziehl–Neelsen (ZN) and Fite–Faraco (FF) stains were used wherever required to demonstrate acid-fast bacilli. The cases were analyzed and categorised according to the clinical and histopathological observations.

A total of 80 cases were included in the present study. Microscopic findings were observed, correlated, and the

results were tabulated. The age distribution of the cases is shown in [Fig. 1]. Maximum cases were in the 21–40-year age group, followed by 41–60 years age group.

A slight male predominance was observed, with a male-to-female ratio of 1.16:1 [Table. 1]. In this study, males were affected more by infectious pathologies such as leprosy, whereas females were more affected by non-infectious conditions like granuloma annulare and fungal infections.

Histopathological diagnoses were classified into three broad categories: infectious, non-infectious, and miscellaneous [Table. 2]. Infectious pathology accounted for 72 cases (90%). The non-infectious category included 4 cases (5%), comprising three cases of granuloma annulare and one of sarcoidosis. Four cases (4.35%) were grouped under miscellaneous causes. The clinical presentations of some of the patients have been depicted in [Fig. 1].

Leprosy was the predominant infectious type of granulomatous pathology (49/80 cases), with indeterminate leprosy subtype as the most common (16 cases; 32.7%). Leprosy was most commonly noted in the 21–40-year age group. Clinico-histopathological concordance was observed in 34 cases (42.5%). The photomicrograph showing the microscopic features in different granulomatous lesions is depicted in [Fig. 2].

Cutaneous granulomatous comprise a variety of disorders sharing the common histopathological observation of granuloma formation[4]. Nearly similar histological patterns may be observed due to diseases of different etiologies, even though a single etiology may produce variable histological picture[5]. Incidence and prevalence of different granulomatous dermatitis depends on the geographic location. Many skin granulomatous lesions show similar histomorphological findings and even a single disease can show variable histological features. Granulomatous inflammation is a type-IV hypersensitivity reaction to an antigen.

In the present study, most of the patients were in the 21–40-year age group (38.8%), followed by 41–60 years (26.3%). Similar findings were reported by previous authors, who observed the highest incidence in the 21–40-year age group[4, 6, 7]. Comparable results were also noted by Permi et al. and Potekar et al.[7, 8]. In contrast, Queirós et al reported 51–60 years as the most frequently affected age group[9].

Male predominance was noted in the present study (71.01%), consistent with the findings by some other authors[3, 4, 8, 10]. However, Zafar et al. and Kumbar et al. reported a female predominance[11, 12]. These differences could be attributed to the geographical distribution or the type of the set up.

Infectious causes constituted the most common aetiology of skin granulomas (90.0%), followed by equal proportion of non-infectious causes and miscellaneous lesions (5.0%) each. These findings are in concordance with the previous studies which also reported infectious etiology as the most common category[4, 10, 13, 14]. In contrast, Queirós et al found non-infectious lesions to be more common, probably due to their geographical and socioeconomic differences[9].

Leprosy (Hansen’s disease) comprised of the commonest infectious aetiology of cutaneous granuloma in our study, with indeterminate leprosy being the most frequent subtype. These findings are consistent with the earlier published reports[4, 15]. However, Ahmed et al. and Potekar et al. reported borderline tuberculoid leprosy as the most common variety[8, 14]. This difference could be due to difficulty in reporting of the Indeterminate subtype.

Cutaneous tuberculosis was the second most common infectious etiology, with lupus vulgaris being the predominant subtype. Clinico-histopathological concordance was observed in 63.4% of cases, which is comparable to the other studies that reported a concordance rate that ranged from 61% to 92%[3, 4, 7, 13, 16]. Lupus vulgaris was the most common subtype as reported previously by other authors as well[1, 5, 17, 18].

Special stains play a pivotal role in the diagnosis of cutaneous granulomas. Acid-fast bacilli were demonstrated in 34 cases using modified ZN stain and in 10 cases using Fite–Faraco stain. Similar observations have been reported in the earlier published reports[6, 16, 18].

Infections remain the most important cause of cutaneous granulomatous diseases, with leprosy as the commonest etiology. Despite great efforts and vigorous newly launched national health programs aimed at eradicating leprosy, it continues to pose as a major public health threat.

Histopathology has a major role in the classification and subtyping of cutaneous granulomas. A through and careful histopathology of skin biopsy, supported by relevant clinical details helps in arriving at a confirmatory diagnosis.

Judicious use of special stains is important, particularly in diagnosing overlapping or problematic cases. Such studies help in the diagnostic accuracy, guide effective treatment, and in reducing the disease burden besides supporting the regional healthcare programs.