Mycosis fungoides (MF), a kind of primary cutaneous lymphoma with relatively indolent biological behavior, represents the most common of cutaneous T-cell lymphomas. According to its biological processes, the characteristics of typical MF lesions can be divided into three stages: patch, plaque, and tumor. 1 Most patients are in the early stage (patch and plaque) for decades due to its unique indolent biological behavior, but once entering the tumor stage, the disease develops rapidly and eventually affects lymph nodes or internal organs. 2 Therefore, early diagnosis and implementing dynamic monitoring of MF are of great significance for its prognosis. Multiple, persistent patch or plaque lesions that occur at unexposed sites may be clinically suspected cases of MF,