30. The paradox

Abstract Introduction Incidental findings on investigations is not uncommon in rheumatology practice. Here such an incidental finding has led to dramatic change in the management of the underlying disease. Case description A 38-year-old gentleman known to have ankylosing spondylitis (AS) since 2008, with radiologically evident sacroilitis on X-ray and MRI, was reviewed routinely in clinic and reported pain and restriction of neck movement and subsequent MRI cervical spine in April 2017 has shown incidental finding of apical fibrosis, but no AS activity. He denied constitutional and respiratory symptoms apart from occasional dry cough. Chest X-ray and high resolution CT scan confirmed the same findings of apical fibrosis in addition to bilateral reticulonodular and fisural changes. Blood tests showed angiotensin converting Eezyme level ACE 65 U/L (normal range 8-65), C-reactive protein <5. Bronchoscopy/biopsy showed non-caseating epitheliod granuloma. ZN stain and culture showed no TB infection. He was reviewed by the respiratory team and felt findings could conceivably fit with sarcoidosis. His dry cough has improved after Benepali was discontinued in June 2017 and no steroids were given. However, had a flare of AS symptoms (ribs and lower back pain and stiffness, right SIJ pain) despite regular etoricoxib and required to start on secukinumab. Discussion Benepali (Etanercept biosimilar) sounds not different from the originator biologic in causing sarcoid-like reactions commonly present as skin rash and lung lesions. Etanercept is associated with a large majority of reported anti-TNF induced sarcoid-like cases, not effective in treating sarcoidosis and may even exacerbate it. However, there are few reports of adalimumab induced sarcoid-like reactions that resolved when treated with etanercept. Paradoxical reaction to one TNF alfa inhibitor does not preclude the use of other TNF blocking agents including etanercept. Key learning points Lung lesions after exposure to anti-TNF warrants investigating a wide range of differential diagnoses. Paradoxical sarcoid-like reactions can occur with anti-TNF treatment and resolves on discounting it. Alternative biologic in ankylosing spondylitis might be a challenge. Conflicts of interest The authors have declared no conflicts of interest.