AB0769 EROSIVE SYNOVITIS, DACTYLITIS, HYPERCALCAEMIA, LYMPHADENOPATHY, ELEVATED SERUM ACE & HYPOTHYROIDISM – AN UNUSUAL PRESENTATION OF IGG4-RELATED DISEASE

Background: IgG4-related disease (IgG4-RD) is a fibroinflammatory disorder which can affect almost any tissue in the body. We describe challenging case of IgG4-RD reflects great heterogeneity this disease. Objectives: A 49-year-old Mauritanian gentleman was referred to Rheumatology with chronic progressive symmetrical synovitis affecting upper and lower limbs. He had no features suggestive spondyloarthropathy or connective Blood tests revealed raised C-reactive peptide (CRP) 194 mg/L erythrocyte sedimentation rate (ESR) 46 mm/hr. His rheumatoid factor anti-cyclic citrullinated antibodies were negative. Anti-nuclear antibody weakly positive at 1:80 speckled pattern, but extractable nuclear antigen antibodies, anti-double-strand DNA-antibodies anti-neutrophil cytoplasm Complement proteins creatine kinase normal. Radiographs hands feet demonstrated widespread erosive changes worst metacarpophalangeal, metatarsophalangeal first tarsometatarsal joints, as well swan-neck deformities fifth phalanges both hands. Chest radiograph serological virology screen unremarkable. subsequently diagnosed seronegative inflammatory arthritis treated intramuscular methylprednisolone. awaiting subcutaneous methotrexate. Methods: hospitalised shortly after worsening polyarthritis hypercalcaemia (3.34 mmol/L). Examination synovitis, new lymphadenopathy dactylitis. Other investigations normocytic anaemia (Hb 80 g/dL, MCV fL), neutrophilia (20 x 10 9 /L), eosinophilia (4 thrombocythaemia (500 hypoalbuminaemia (25 g/L), CRP 200 ESR 60 All immunoglobulins IgG 30.5 g/L. IgG4 subset 3.0 Parathyroid hormone low (< 0.7 pmol/L) vitamin D 125 nmol/L. Thyroid function, myeloma blood tumour markers film blasts. Serum angiotensin-converting enzyme (ACE) elevated 171.9 U/L. CT-chest-abdomen-pelvis an enlarged thyroid retrosternal extension above diaphragm. Results: Biopsies gland submandibular lymph node lymphoplasmacytic > 40% cells. Neither biopsy showed evidence sarcoidosis, tuberculosis malignancy. weaning regimen high-dose oral corticosteroids resulting normalisation haematological, biochemical parameters. musculoskeletal pain, swelling early morning stiffness significantly improved too. Subcutaneous methotrexate commenced titrated upwards 20 mg. Two months later, his relapsed upon reduction corticosteroids. Again, there marked response ESR. also developed hypothyroidism (TSH 100 mU/L, T4 0.5 µg/dL, TPO-antibody). Repeat hand radiographs severe (Figure 1). awaits commencement rituximab. Figure 1. Plain demonstrating extensive arthritis. Conclusion: This unique presentation for rare There are few reports causing rheumatoid-like hypercalcaemia. Furthermore, report far we know, associated dactylitis serum ACE. Prior biopsy, our main working diagnoses sarcoidosis lymphoproliferative The peculiar necessitated second opinion via national MDT who confirmed histological diagnosis IgG4-RD. hope that interesting highlights importance histology complex cases. In addition, adds multitude clinical manifestations Disclosure Interests: None declared