Primary pulmonary extranodal natural killer/T-cell lymphoma (ENKTL), nasal type: Two case reports and literature review

INTRODUCTION: Extranodal natural killer/T-cell lymphoma (ENKTL) – nasal type is an aggressive form of malignant non-Hodgkin lymphoma with a very poor prognosis. Especially primary pulmonary ENKTL is a relatively rare form of non-Hodgkin lymphoma. Until now, the prevalence of primary pulmonary ENKTL is unknown. Since 2001, only 18 cases of primary pulmonary ENKTL have been published, in addition to the 2 cases reported here. PATIENT CONCERNS: We describe 2 cases of primary pulmonary ENKTL. Both patients were male non-smokers, aged 61 and 49 years. Their main clinical symptoms included cold-like symptoms and intermittent fever (39.3°C and 38.8°C) for some days (40 days and 3 weeks). Both patients had no relevant personal or family medical history. DIAGNOSIS: The patients were initially misdiagnosed with community-acquired pneumonia. Primary pulmonary ENKTL was confirmed by immunohistochemical staining of computed tomography-guided transthoracic needle biopsy specimens. Both cases were positive for CD56, CD3, and in situ hybridization for Epstein-Barr virus-encoded small RNA, but negative for CD20. INTERVENTIONS: Initially, both patients were treated inadequately with intravenous moxifloxacin administration (unknown dosage and 400 mg q.d) in their local hospitals. Once diagnosed with primary pulmonary ENKTL in our hospital, they received 3 cycles of chemotherapy with combined regimens of dexamethasone, methotrexate, ifosfamide, L-asparaginase, and etoposide (SMILE), and in the second patient, bone marrow transplantation was performed following the third chemotherapy cycle. OUTCOMES: Clinical follow-up after the chemotherapy showed that the condition of the first patient progressively deteriorated. He died 2 months following the initial diagnosis. However, the presence of the hemophagocytic lymphohistocytosis gradually improved in the second patient during chemotherapy. Ultimately, the second patient died of acute transplant rejection 6 months after the initial diagnosis. CONCLUSION: The diagnosis of ENKTL should be considered when patients present with fever and expansile consolidation of the lung not responding to antibiotics. The diagnosis depends on histopathology and immunophenotyping. Percutaneous transthoracic needle biopsy is a safe and effective biopsy method. Chemotherapy may improve the prognosis, but this should be confirmed by prospective multicenter studies.