A case of primary pulmonary NK/T cell lymphoma presenting as pneumonia

Primary pulmonary lymphoma, particularly non-B cell lymphomas involving lung parenchyma, is very rare. A 46-year-old male was admitted to the hospital with fever and cough. Chest X-ray showed left lower lobe consolidation, which was considered pneumonia. However, because the patient showed no response to empirical antibiotic therapy, bronchoscopic biopsy was performed for proper diagnosis. The biopsied specimen showed infiltrated atypical lymphocytes with angiocentric appearance. On immunohistochemical staining, these atypical cells were positive for CD3, CD30, CD56, MUM-1, and granzyme B, and labeled for Epstein–Barr virus encoded RNA in situ hybridization. These findings were consistent with NK/T cell lymphoma. We report on a case of primary pulmonary NK/T cell lymphoma presenting as pneumonic symptoms and review the literature on the subject.