Abstract: Gan Lu, Chen Hao, Xiong Jingshu, Fan Xiangshan, Xu Xiulian, Shao Xuebao, Cheng Wei, Zeng Xuesi, Sun Jianfang Department of Pathology, Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College, Nanjing 210042, China （Gan L, Chen H, Xiong JS, Xu XL, Shao XB, Cheng W, Zeng XS, Sun JF）; Department of Pathology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing 210008, China （Fan XS） Corresponding author: Chen Hao, Email: CH76CH@163.com 【Abstract】 Objective To investigate clinical manifestations, histopathological and immunohisto-chemical features of lymphoblastic lymphoma/leukemia with skin lesions as the initial manifestation. Methods Clinical data were collected from 6 cases of lymphoblastic lymphoma/leukemia initially manifesting as skin lesions in Hospital of Dermatology of Chinese Academy of Medical Sciences and Peking Union Medical College between 2012 and 2015, and clinical and histopathological features were retro-spectively analyzed. Results The 6 patients included 4 males and 2 females, of whom, 4 were children or youths, and 2 were adults. The median age of onset was 13.5 years, and the median disease duration was 8.5 months. The skin lesions mainly manifested as single （1 case） or multiple （5 cases） nodules or infiltrative plaques. Histopathological examination showed dense monomorphous infiltrates composed of atypical lymphoid cells in the dermis and subcutaneous adipose tissue. The tumor cells in most cases were medium-sized with scant cytoplasm, stippled chromatin and small nucleoli. The infiltration of lymphoid cells was separated from the epidermis by a grenz zone. A ′starry sky′ appearance was observed in 1 case. Based on the immunopheno-types, 2 cases were diagnosed as B-cell lymphoblastic lymphoma, 2 as T-cell lymphoblastic lymphoma, and other 2 as B/T-cell biphenotypic lymphoblastic lymphoma. The treatment of this disease was difficult. After chemotherapy, 1 patient achieved complete remission, and 2 patients achieved partial remission. Conclusion B-cell and T-cell lymphoblastic lymphoma have similar clinical and histopathological characteristics, and can only be distinguished from each other based on immuno-phenotypes, thus early bone marrow and imaging examinations are particularly important.