Giant-cell arteritis associated with myelodysplastic syndrome: French multicenter case control study and literature review.

Myelodysplastic syndromes (MDS) and MDS/myeloproliferative neoplasms (MDS/MPN) can be associated with giant cell arteritis (GCA). In this nationwide study by the "French Network of dysimmune disorders associated with hemopathies" (MINHEMON) the objective was to evaluate characteristics, treatment and outcome of GCA MDS-MDS/MPN.Retrospective analysis of patients that presented a MDS or MDS/MPN associated with GCA. Treatment efficiency, relapse-free and overall survival of GCA MDS-MDS/MPN were compared to GCA alone.Twenty-one patients with GCA MDS-MDS/MPN were included with median age 76 [42-92], M/F ratio 2.5, 8 MDS with multilineage dysplasia (38%), 4 chronic myelomonocytic leukemia (19%), at low or intermediate risk according to IPPS and IPSS-R. The prevalence of headaches, jaw claudication and anterior ischemic optic neuropathy was significantly lower in patients with GCA MDS-MDS/MPN compared to idiopathic GCA (14.3%, 0% and 0% versus 30%, 25%, and 25%, respectively; p < .05). Other clinical and histology findings were similar. All GCA patients received steroid therapy as first-line treatment. Complete or partial response was observed in 14 GCA MDS-MDS/MPN patients (66.7%), of whom 6 (28.6%) received combined immunosuppressive therapies (versus 10% of idiopathic GCA; p = .07). Relapse incidence was similar in the two groups. Steroid dependence was more frequent among GCA MDS-MDS/MPN patients (12 (57%) versus 18 (22.5%); p < .05). Relapse-free and steroid-free survivals were significantly decreased in GCA MDS-MDS/MPN patients (log rank 0.002 and 0.049 respectively), but not overall survival.Characteristics of GCA MDS-MDS/MPN seem different than idiopathic GCA, with a distinct clinical phenotype and poorer outcome with a higher risk of steroid dependence and relapse.