Malignant pulmonary lymphoma is very rare and the majority of which are B-cell lymphomas. Since primary pulmonary extranodal natural killer (NK)/T-cell lymphoma, nasal type (ENKL) is difficult to diagnose and associated with poor prognosis and aggressive course, some cases are diagnosed at the postmortem autopsy. We report a case of a 53-year-old man with primary pulmonary ENKL diagnosed by video-assisted thoracoscopic surgery (VATS) lung biopsy. This case explains the importance of VATS lung biopsy and in-depth evaluation, including flow cytometry, chromosome, genetic, and immunostaining tests, when primary pulmonary malignant lymphoma is suspected.