The use of a drug-coated balloon (DCB) to treat dysfunctional arteriovenous fistula (AVF) has shown promising results. After percutaneous coronary intervention with DCB, late lumen enlargement (LLE) often develops in the early follow-up phase, but questions regarding the natural history of changes in lesions after DCB angioplasty have not been clearly elucidated. Here, we reported on a patient in whom angiography and angioscopy were performed immediately and 4 months after DCB angioplasty to treat cephalic vein stenosis of the dysfunctional AVF. Immediately after DCB application, angiography showed good dilatation and blood flow and mild vascular dissection that did not affect blood flow. Angioscopy showed that although the balloon had damaged the intima and the paclitaxel particles had adhered to the vessel wall. Four months after DCB treatment, follow-up angiography and angioscopy were performed. Angiography showed LLE in the cephalic vein of the AVF that had been treated by DCB angioplasty. Angioscopy showed that the intima of the vessel had almost completely healed, and the paclitaxel particles had disappeared. LLE might occur when DCB is used for AVF.