Inert natural killer/T-cell lymphoma with large cell transformation: report of one case and review of literature

Abstract

Objective To investigate the clinicopathologic features of inert natural killer/T (NK/T)-cell lymphoma with CD30-positive large cell transformation. Methods The pathological data of one patient diagnosed as inert NK/T-cell lymphoma with CD30-positive large cell transformation in the Third Hospital Affiliated to Soochow University from April 2006 to March 2017 were collected. The histopathological features and immunohistochemical phenotype of the patient were observed and followed up. Results The patient received biopsy twice in April 2006 and March 2017. The first tumorectomy in sacral canal showed that diffuse and small lymphoid cell hyperplasia, irregular nucleus, granular chromatin, unobvious nucleolus, focal necrosis. Immunohistochemistry showed CD20(-), CD3(-), ALK(-), CD30(-), CD43(+), CD2(+), CD56(+), TIA-1(+), GrB(+), CD4(-), CD8(-). Finally, the patient was diagnosed as extranodal NK/T-cell lymphoma, nasal type. The microscopic examinations after the second left cervical lymph node biopsy showed large cells infiltrated into the background of small lymphocytes, plentiful cytoplasm, large nuclei, irregular nucleus, part of nuclear folding, obvious nucleolus, mitotic figures visible, visible intravascular tumor suppository, consistent small lymphocytes. Blood vessel invasion could be seen, as wells as consistent small lymphocytes, regular form, less cytoplasm, rare nuclear fission. Immunohistochemistry showed AE1/AE3(-), CD20(-), CD3(+), ALK(-), CD30(+), CD43(+), CD2(+), EMA(-), Ki-67(70%+), CD56(+), TIA-1(+), GrB(+), CD4(-), CD8(-). Finally, the patient was diagnosed as NK/T-cell lymphoma, nasal, recurrence. In situ hybridization showed EB virus encoded RNA (EBER) was positive for two biopsies. Conclusions Inert extranodal NK/T-cell lymphoma is very rare. The pathogenesis is closely related to EB virus infection. Its diagnosis must rely on histopathology and immunohistochemistry. Key words: Natural killer/T-cell lymphoma, nasal type; Inert; Epstein-Barr virus