A 54-year-old man was admitted to our hospital with a painful left axillary mass. He had a 27-year history of hemodialysis for end-stage kidney disease because of chronic glomerulonephritis. He had a right radial artery-cephalic vein arteriovenous fistula and left nonfunctioning arteriovenous fistula. Computed tomography imaging showed a left axillary arterial mass with peripheral hematoma and multiple lung tumors. On hospital day 3, he showed disturbances in consciousness as well as enlargement of the axillary mass and hematoma. We performed emergency surgery to resect the left axillary tumor. The patient was diagnosed with angiosarcoma upon histopathological examination of the resected specimen on hospital day 15. Because his condition was extremely poor, we provided supportive care to him, not chemotherapy. He expired on hospital day 25. Angiosarcoma remains a rare disease; however, this case highlights the importance of including angiosarcoma in the differential diagnosis for upper extremity pain in patients undergoing hemodialysis.