Intravascular NK/T-cell lymphoma is a rare subtype of non-Hodgkin lymphoma characterized by histologic feature of atypical lymphoid cells involving blood vessels. It is not classified as an independent entity within the WHO classification, but it has been shown to be a distinctive phenotype different from other lymphoma of the NK/T-cell lineage. A 57-year-old woman without any history of specific medical history visited our clinic with poorly demarcated indurated subcutaneous tender nodules on her right thigh lasting over 2 months. The biopsy performed under the possibility of panniculitis revealed engorged dermal and subcutaneous vessels filled with atypical lymphoid cells. The positivity of CD3 and CD56, and the negativity of CD4, CD8, CD20 and CD30 were confirmed by immunohistochemistry. Also, the presence of Epstein-Barr virus (EBV) infected cell was detected by in situ hybridization for the tissue and EBV PCR for the serum. No other organ involvement other than skin was identified on further examinations. The patient had been responded favorably to chemotherapy and autologous hematopoietic stem cell transplantation, and the cutaneous lesion had been resolved. In summary, we present a case of primary cutaneous intravascular NK/T-cell lymphoma showing clinical appearance of panniculitis. This case provides clues to understand the clinical manifestations of a disease that has not yet been clarified.