A Rare Association of Interstitial Lung Disease in Ankylosing Spondylitis: A Case Report and Review of Early Detection and Multidisciplinary Management.

Ankylosing spondylitis (AS) is a chronic inflammatory disorder of the axial skeleton, occasionally complicated by uncommon but increasingly recognized pulmonary involvement such as interstitial lung disease (ILD). We report a 35-year-old woman with a year-long history of inflammatory back pain and peripheral arthritis who fulfilled clinical and radiologic criteria for AS. Despite partial response to cDMARDs, she developed a productive cough. High-resolution CT revealed right upper-lobe ground-glass opacities consistent with early cellular ILD, supported by spirometry showing a moderate restrictive defect and negative autoimmune serology excluding overlapping connective tissue diseases. Conservative pulmonary monitoring and escalation to secukinumab resulted in marked improvement in both musculoskeletal and respiratory symptoms. This case highlights clinically under-recognized pulmonary involvement in AS, including early inflammatory (cellular) ILD, emphasizing diagnostic challenges and the importance of timely imaging and multidisciplinary management.