Giant Cell Arteritis which Developed after the Administration of Granulocyte-colony Stimulating Factor for Cyclic Neutropenia.

A 78-year-old woman diagnosed with cyclic neutropenia 5 years previously had been treated with recombinant granulocyte-colony stimulating factor (G-CSF). She developed fever, tenderness and distension of temporal arteries after the treatment with G-CSF. Magnetic resonance imaging and ultrasonography revealed wall thickening of the temporal arteries. She was therefore diagnosed with giant cell arteritis (GCA). Small vessel vasculitis has been reported as a complication of G-CSF. However, the development of large vessel vasculitis after G-CSF treatment is quite rare. To our knowledge, the present case is the first report of GCA suspected to be associated with coexisting cyclic neutropenia and G-CSF treatment.