Etiology of granulomatous inflammation: A retrospective study of 174 children in a tertiary care center

Objective: To investigate granulomatous inflammation etiology based on clinical history and ancillary tests.Methods: Children aged <18 years with biopsy proven granulomatous lesions in any tissue specimens between January 2014 and January 2022 were included in the study. The diagnosis was based on the results of immunohistochemical staining, molecular tests, culture, serology, radiological and other auxiliary laboratory tests. Diagnoses were categorized into infectious and noninfectious causes. Results: In total, 174 patients with granulomatosis inflammation confirmed by histopathology were analyzed. Approximately 59.2% patients were males, and the median age was 4.48(IQR 2.36-6.39) years(range: 16 months-18 years). The tissues/organs that were most commonly biopsied were lymph node, bone, skin, and lung(51.1%, 17.8%, 9.2%, and 5.7%, respectively). Infectious and non-infectious causes were identified in 73.0% and 12.6% patients, respectively, in terms of granulomatosis inflammation etiology; however, no cause was identified in 14.4% patients. The most common infectious cause was tuberculosis(in 51.7% patients), followed by toxoplasmosis, aspergillosis, mucormycosis, leishmaniasis, and cat-scratch disease(in 8.6%, 5.7%, 1.7%, 1.7%, and 1.1% patients, respectively). The common non-infectious cause was chronic granulomatous disease. Histopathological evaluation revealed granulomatosis inflammation in 33.3% patients, necrotizing granulomatosis inflammation in 30.5% patients, and caseating granulomatosis inflammation in 12.1% patients. When the pathology results of patients with and without tuberculosis were compared, the incidence of caseating granulomatosis inflammation(P=0.003) and necrotizing granulomatosis inflammation(P=0.005) was higher in patients with tuberculosis.Conclusions: Chronic granulomatous disease is the most common non-infectious cause in children. Moreover, primary or secondary immune deficiencies may cause granulomatosis inflammation, especially in pediatric patients.