Erdheim-Chester disease is a rare non-Langerhans-cell histiocytosis with bone and organ involvement. A 76-year-old man presented with low back pain and a history of visits for exertional dyspnea. We diagnosed him with anemia of chronic disease, cytopenia related to chronic illness, chronic renal failure due to hypertension, and hypothyroidism. However, we could not determine a definite cause or explanation for the cytopenia. Multiple osteosclerotic axial skeleton lesions and axillary lymph node enlargement were detected by computed tomography. Bone marrow biopsy revealed histiocytic infiltration, which was CD68-positive and CD1a-negative. This report describes an unusual presentation of Erdheim-Chester disease involving the bone marrow, axial skeleton, and lymph nodes.