Simultaneous Presentation of Giant Cell Arteritis and Myelodysplastic Syndrome in an Elderly Japanese Man.

An 81-year-old Japanese man presented with constitutional symptoms and anemia and was diagnosed with giant cell arteritis (GCA) and myelodysplastic syndrome (MDS) simultaneously. His symptoms and anemia improved promptly with steroids; however, the MDS rapidly progressed to overt leukemia. While MDS patients are at an increased risk of autoimmune diseases, an association with GCA has rarely been reported. This case illustrates the importance of considering GCA as a cause of anemia in elderly patients if MDS is already diagnosed, even in countries where the prevalence of GCA is very low. The simultaneous development of GCA and MDS suggests a common pathogenetic link between these two diseases.