A Rare Cause of Pleural Effusion: Ankylosing Spondylitis

Ankylosing spondylitis (AS) is a seronegative spondyloarthropathy involving the axial skeleton and major joints. Pleuropulmonary involvement is rare manifestation of AS mostly presented as apical fibrobullous disease and pleural thickening. Herein, we report a rare case with right sided pleural effusion in a male patient that was determined on a chest x-ray performed routinely before initiation of anti-TNF therapy. Pleural effusion was a lymphocytic exudate with a normal glucose level. The histopathological examination of closed pleural biopsy revealed nonspecific chronic inflammatory cell infiltration. The patient was followed up with etanercept treatment. One year after the initiation of therapy, due to persistent pleural effusion, video assisted thoracoscopic surgery was performed. Pleural biopsies were also consistent with chronic inflammation.