Extranodal NK/T cell lymphoma, nasal type, is an Epstein-Barr virus-associated lymphoma that most commonly involves the nasal cavity and upper respiratory tract. Lung involvement by NK/T cell lymphoma is rare and seldom reported in the literature. We describe the unusual case of a 41-year-old male with NK cell lymphoma, nasal type, who presented with massive secondary lung involvement 2.5 years after the detection of a retroperitoneal mass. The diagnosis was made by open lung biopsy. Despite aggressive treatment, the patient died shortly after the initiation of therapy. Lung involvement by NK/T cell lymphoma occurs most commonly as part of widely disseminated disease and carries a poor prognosis for the patient. Novel agents and innovative therapies need to be developed for this aggressive lymphoma.