Histomorphological Evaluation of Granulomatous Dermatitis: A Single-Center Experience

Granulomatous dermatitis represents a heterogeneous group of chronic inflammatory skin disorders characterized by the accumulation of histiocytes in the dermis due to various infectious and noninfectious etiologies. In most cases, histopathological evaluation alone is insufficient for establishing a specific diagnosis. Early and accurate diagnosis requires clinicopathological correlation. Therefore, this study aimed to characterize the histomorphological features of granulomatous dermatitis and to assess the impact of clinicopathological correlation on diagnostic accuracy. In this retrospective study, 91 cases diagnosed between 2021 and 2024 at a single center were evaluated based on clinical, laboratory, and histopathological parameters. The most common histopathological pattern was the necrobiotic type (47.3%), followed by sarcoidal (16.5%) and foreign body (14.3%) granulomas. Among multinucleated giant cells, Langhans-type cells were the most frequently observed (36.3%), and granulomas were predominantly localized within the reticular dermis (83.5%). Clinically, plaques constituted the most common lesion morphology (52.7%), and lesions were mainly distributed over the head-neck and upper extremity regions. A strong correlation between pathological and dermatological diagnoses was identified (r = 0.748; p < 0.001), with complete concordance observed in 60.4% of cases. Statistically significant associations were found between pathological diagnosis and lesion type, giant cell morphology, granuloma pattern, epithelial alterations, and vasculitis (p < 0.05). In conclusion, histomorphological evaluations must be supported by clinical and laboratory data to ensure diagnostic accuracy. This integrated approach substantially enhances diagnostic reliability in granulomatous dermatitis.