AB1164 Immunoglobulin use in granulomatous myositis with background of thymoma and systemic lupus erythematosus
Authors: Y.K. Kwok, M.H. Leung
Journal: Annals of the Rheumatic Diseases (2018)

<h3>Background</h3> Contracturing granulomatous myositis is rare in clinical practice. <h3>Objectives</h3> To report a case with systemic lupus erythematosus presented with contracturing granulomatous myositis and previous history of thymoma which responded to intraveous immunoglobulin (IVIG). <h3>Methods</h3> A case report from a local hospital in asia <h3>Results</h3> A forty-two year old gentleman presented with polyarthalgia, raynaud's phenomenon, photosensitivity with elevated ANA and anti-dsDNA was diagnosed to have SLE in 2014 in rheumatology clinic. His lupus activity was stable on hydroxychloroquine (HCQ) and low dose steroid for the arthritis control. In May 2015, an anterior mediastinal mass was noted on CT thorax for symptoms of chronic cough and chest pain. Operation was performed in <sup>Aug 2015</sup> with incomplete excision with invasion into lung, percardium and nodal metastes. Pathology showed thymoma. Adjuvant radiotherapy 60 Gys in 30frs was given and completed in .<sup>Dec 2015</sup> He had stable lupus activity all along until .<sup>Aug 2017</sup> He was hospitalised with sudden onset of proximal muscle weakness which rendered patient unable to walk. Elevated CK level was up to 5354 IU/L. There was no evidence of concurrent infection. Myositis panel showed Strongly positive anti-PM/SCL, borderline positive Anti Mi2 alpha and PM Scl 100. Dysphagia was documented by speech therapist. Muscle biopsy of right quadriceps was performed by neurologist and showed granulomatous myositis. Electromyography (EMG) showed myopathic changes. Lupus myositis was diagnosed with dysphagia. Patient was started on IVIG (0.4 gm/kg/day) for 5 days and high dose steroid (prednisolone 30 mg daily orally) was initiated concurrently. CK showed good response and normalised with improvement in the lower limb power within one month. Patient was able to walk and discharged home. However he was re-admitted one month later for generalised tightening of 4 limbs and contractures over elbows and knee joints with intense pain and limited range of movement. CK level was normal in this admission. PET-CT showed a small (2.2 × 1.4 cm SUV Max5.5) right anterior mediatstinum lesion near to surgical site. It was suspicious of local recurrence. Cardiothoracic surgeon was consulted and suggested not for further surgery since of high operative risk. In view of worsening of contractures and weakness over lower limbs, despite normalisation of CK level and quiescent lupus serology, further courses of IVIG monthly were commensed. Steroid dosage was able to titrate down to prednisolone 9 mg daily orally gradually with improvement in 4 limbs power and halting of further contractures. No more dysphagia was documented afterwards. With the incomplete excision of thymoma, further discussion with oncologist and neurologist on future treatment plan ensued. Role of IVIG in controlling the underlying autoimmune phenonomenon attributed by the underlying malignancy was unknown. IVIG was stopped after 6 courses and oncologist proceeded with palliative chemotherapy. <h3>Conclusions</h3> IVIG use in contracturing granulomatous myositis in a lupus patient with underlying thymoma may be useful. <h3>References</h3> [1] NJ Simmonds, BI Hoffbrand. Contracturing granulomatous myositis: a separate entity. Journal of Neurology, Neurosurgery, and Psychiatry1990; 53:998–1000 [2] S. Prieto-Gonzalex, et al. Diagnosis and classification of granulomatous myositis. Autoimmunity Reviews13(2014) 372–374 <h3>Acknowledgements</h3> Division of Neurology, Department of Medicine, Queen Elizabeth Hospital <h3>Disclosure of Interest</h3> None declared