A rare optical coherence tomography finding of a striped, low-attenuation plaque protruding into the lumen in in-stent restenosis

BACKGROUND: In-stent restenosis (ISR) remains a clinical challenge in the drug-eluting stent (DES) era. Neoatherosclerosis is a recognized mechanism, but tissue responses after drug-coated balloon (DCB) therapy may present with atypical morphologies. CASE PRESENTATION: We report a 55-year-old man with recurrent angina and ISR nine years after DES implantation and one year after DCB angioplasty. Optical coherence tomography (OCT) revealed a distinctive striped, low-attenuation plaque protruding into the lumen from outside the stent struts. This lesion lacked lipid, calcification, or macrophages, making it difficult to classify as typical neoatherosclerosis. The morphology suggested layered neointimal remodeling with possible thrombus organization after DCB treatment. The lesion was successfully treated with excimer laser coronary angioplasty, scoring balloon dilatation, and DCB angioplasty. CONCLUSION: This case illustrates an atypical OCT morphology observed in recurrent ISR after DCB angioplasty. Recognition of such atypical ISR morphologies may enhance understanding of neointimal healing after DCB treatment and guide interventional strategies.