[Extranodal NK/T-cell lymphoma arising from soft tissue of the left forearm].

A 72-year-old man with extranodal natural killer cell lymphoma (ENKL) presented with a painless swelling of the left forearm. He was initially diagnosed as having a bacterial cellulitis and received antimicrobial therapy. However, his left arm became increasingly swollen in association with fever and redness of the lesion. Therefore, he underwent focal dissection. Because of persistent swelling, the left arm was rebiopsied 9 months later, and a diagnosis of ENKL developing in the subcutis was established. He was treated with focal radiation therapy in combination with dexamethasone, etoposide, ifosfamide, methotrexate and L-asparaginase. The lesion was significantly reduced in size but did not disappear completely. Two months later the lesion became necrotic, although swelling of the forearm lesion, left axillary and cervical lymph nodes were kept under control. We then performed amputation of the left forearm since it could not be saved medically. The patient currently remains alive and well without progression 2 years after amputation. When evaluating panniculitis, which is difficult to cure, ENKL should be considered in the differential diagnosis and treated appropriately.