CT Features of Granulomatous-Lymphocytic Interstitial Lung Disease (GLILD): The "Kebab Sign" as a Marker to Support Differential Diagnosis.

Objective: In this study, we aimed to evaluate high-resolution computed tomography (HRCT) features of granulomatous-lymphocytic interstitial lung disease (GLILD) in patients with Common Variable Immunodeficiency (CVID), and to describe a novel imaging feature-termed the "Kebab sign"-as a potential radiologic marker of GLILD. Materials and Methods: We retrospectively reviewed HRCT scans of 15 patients with GLILD diagnosed between 2005 and 2025 at a single institution (seven biopsy-confirmed, eight probable diagnoses based on multidisciplinary consensus). CT patterns were assessed for predominant morphology (nodular, reticular, alveolar, fibrotic), distribution (axial and cranio-caudal), and presence of extra-parenchymal findings. Nodules were characterized by size, density, morphology, and the presence of air bronchograms. The "Kebab sign" was defined as nodules aligned along bronchial structures with associated peribronchial thickening. Results: All patients demonstrated a diffuse nodular pattern, with non-calcified macronodules in 100% and micronodules in 60% of cases. Air bronchograms were present in 87% of macronodules. A peri-bronchovascular distribution with lower lung predominance was observed in the majority of cases. The "Kebab sign" was identified in 87% of patients. Splenomegaly and hilar/mediastinal lymphadenopathy were observed in 75%. In 20% of patients, fibrosing features were also present, particularly in older individuals. Conclusions: HRCT findings of GLILD typically include peri-bronchovascular nodules with lower lobe predominance, typically associated with splenomegaly and mediastinal lymphadenopathy. The newly described "Kebab sign," reflecting nodular alignment along thickened bronchial structures, may represent a useful imaging clue to support the diagnosis of GLILD.