Abstract： An 18-year-old female presented with painful erythema and nodules on both legs for more than 2 years.Dermatological examination showed irregularly sized,mildly indurated,tender,deep subcutaneous nodules arising in diffused infiltrated dark erythematous patches in the inner and posterior region of the left leg.Histopathology showed no significant changes in the epidermis.There were perivascular lymphoid cell infiltrates in the dermis and subcutis.Multiple sites of necrosis of blood vessel walls with vascular occlusions were noted.The lumens of some blood vessels were filled with lymphocytes,among which were many atypical cells with hyperchromatic nuclei and pathologic mitotic figures.Immunohistochemistry showed that lymphocytes in the cavities of blood vessels were positive for CD3(+++),CD3ε(+++),CD2(+),CD56(+++),granzyme B(+++),perforin(+++),CD30(+),Ki67 (+++,100％ ),but negative for CD20,CD5,CD7,CD4,CD8,TdT,anaplastic lymphoma kinase,early membrane antigen (EMA) or pan cytokeratin (pCK).The endothelial cells lining the blood vessels stained positively for CD34.The intravascular lymphocytes were also positive for EBER1/2 by in situ hybridization.A diagnosis of cutaneous intravascular NK/T cell lymphoma was made.