P056 Rheumatology haematology interface: an unusual case of aortitis

Abstract

Abstract Background/Aims In rheumatological practice it in not unusual to see patients with haematological involvement. We would like to present a very rare diagnosis of Erdheim-Chester disease presenting as retroperitoneal fibrosis and large vessel vasculitis who failed to respond to conventional treatments with steroids and methotrexate. Methods A 71-year-old man presented to haematology with retroperitoneal mass. This was investigated with CT thorax, abdomen and pelvis and a biopsy was performed which was negative for haematological malignancies. However, CT scan picked up thickening of aorta and a PET scan was performed subsequently confirming widespread aortitis and peri-renal mass thought to be consistent with retroperitoneal fibrosis. The patient was started on reducing course of oral steroids with a working diagnosis of retroperitoneal fibrosis with large vessel vasculitis. Results Subsequent staining for IGG-4 was negative and biopsy was not typical with IgG4 cells. The patient was started on high doses of oral steroids by haematologist with Methotrexate started subsequently by rheumatologist due to persistent changes on PET scan, high inflammatory markers and worsening of patient with generalised malaise, weight loss and fatigue. The patient failed to respond to uptitrated doses of methotrexate and was discussed with a specialist unit for consideration of anti-IL6 tocilizumab to control his large vessel vasculitis. On discussion of imaging in MDT, unusual appearance with sparing of ureters, splaying of peri-nephric fat, lack of IgG4 cells pointed towards an alternative diagnosis. Conclusion The patient was subsequently discussed in the national adult histiocytosis meeting with national and international haematologists. The clinical presentation, radiological appearance was thought to be classic of Erdheim-Chester disease, a rare form of adult onset histiocytosis. After further discussions with specialist centre the patient has been commenced on trametinib, a MEK inhibitor treatment (cell tissue negative for BRAF mutation). The patient has recently developed heart failure and has undergone right heart catheter which has found extremely rare pulmonary artery vasculitis too. Disclosure S. Raghuvanshi: None. B. Tarar: None. A. Shaaban: None.