Clinicopathologic evaluation of granuloma annulare: Study of 136 Iranian cases, south of Iran.

BACKGROUND AND OBJECTIVES: Granuloma annulare (GA) is a benign skin disorder with various histopathologic features that are rarely investigated in Iranian population. We performed this study to find out the clinical and histopathologic features of GA in our referral centre.

METHODS: One hundred-thirty-six patients with biopsy-proven GA were reviewed. Clinical data and pathological features were recorded.

RESULTS: One hundred-eight female patients and 28 male patients (Female/male ratio: 3.85) with mean age of 42.54 ± 21.2 years (range: 2-83 years) were recruited. Eighty-eight (64.7%) patients had interstitial infiltrative pattern and 48 (35.3%) patients had complete palisading granulomas. The infiltrate occupied both upper and lower dermis in most of the cases (67.7%). Significant mucin was detected more commonly in complete GA compared to interstitial GA ( p  = 0.019), but inflammation degree, eosinophils, plasma cells, and giant cells were not different between two subtypes of GA ( p  > 0.05). The significant inflammation contained more significant plasma cells ( p  = 0.006). The significantly more giant cells were detected in patients between 20 and 60 years of age ( p  = 0.015); but other factors were not different between age groups.

CONCLUSIONS: In our study, the prevalence of GA in women was significantly higher than in men. Interstitial GA was the more common histological subtype and the inflammation was less severe and the infiltrate was mostly pandermal in our cases. More severe inflammation contained more plasma cells, and more dense giant cells were seen in middle aged patients.