Abstract Background Although coronary artery involvement in patients with IgG4-related disease (IgG4-RD) is rare, emergency revascularisation is recommended for managing acute coronary syndrome. However, coronary aneurysm formation and stent migration after sirolimus-eluting stent implantation have been reported for this disease. Thus, new treatment modalities are warranted for the management of coronary artery disease in this vasculitis. Case summary A 70-year-old male who experienced progressive chest discomfort for 1 month underwent cardiac examination. Coronary computed tomography angiography (CCTA) revealed right coronary artery hypoplasia, coronary artery aneurysm with severely calcified stenosis in the proximal left anterior descending artery (LAD), and subtotal obstruction in the mid-LAD. The left circumflex artery (LCX) also had stenosis and dilated lesions. Additionally, diffuse perivascular soft tissue thickening was observed in the mid-LCX. Percutaneous coronary intervention was performed for the proximal- and mid-LAD lesions. Rotational atherectomy with low-pressure drug-coated balloon (DCB) dilation was considered for these lesions owing to suspicion of vasculitis. The patient was later diagnosed with Sjögren's syndrome and IgG4-RD overlap syndrome. Oral steroids and immunosuppressive drugs were initiated. In a follow-up at 7 and 26 months, late lumen enlargement was observed in the treated area of the LAD, without enlargement of the adjacent aneurysm. CCTA performed after 26 months revealed resolution of the diffuse perivascular soft tissue thickening in the mid-LCX. Discussion To our knowledge, this is the first case report demonstrating favourable outcomes for treatment of a coronary artery lesion attributed to IgG4-RD with DCB, leaving nothing implanted in the coronary artery tree.