A percutaneous coronary intervention (PCI) is known to be one of effective methods in the treatment of coronary artery disease. However, restenosis remains a major limitation to a PCI. Although neointimal cell proliferation is suspected to be the major cause of coronary stent restenosis, few histological characterizations of recurrent instent restenosis exist. We report a case of a 61-year-old man suffering from unstable angina due to secondary coronary in-stent restenosis in the proximal left anterior descending artery (LAD). An atherectomized tissue, obtained by a directional coronary atherectomy, showed myxoid tissue, characterized by a few stellate smooth muscle cells in the abundant extracellular matrix, which was blue-colored proteoglycan on modified Movat staining.