The diagnosis of ENKTCL-NT depends on histological findings that biopsied tissue infiltrates contain lymphocytes that express CD3ε, cytotoxic molecules (granzyme B, perforin, TIA1), and EBV. Bone marrow examination is recommended to determine its involvement in this disorder. Whole body PET-CT scans are recommended to determine the extent of disease at presentation as well as to follow the effects of therapeutic interventions. The tumor load of each individual's disease as well as response to therapies has also been estimated by assaying plasma levels of EBV DNA. ENKTCL-NT can be mimicked by two benign diseases which involve the excessive proliferation of non-malignant<unk>  cells in the GI tract viz., Natural killer cell enteropathy, a disease wherein<unk>  cell infiltrative lesions occur in the intestine, colon, stomach, and/or esophagus, and lymphomatoid gastropathy, a disease wherein these cells infiltrative lesions are limited to the stomach. Another lymphoproliferative disorder of the GI tract, indolent T cell lymphoproliferative disorder of the gastrointestinal tract may also mimic ENKTCL-NT. This chronic disorder involves the proliferation of CD+4, CD8+, CD4-/CD8-, or CD4+/CD8+ T cells in the mucosal layers of the GI tract to give a variety of GI tract symptoms. While generally a persistent and benign disorder, a small but significant percentage of cases have progressed to aggressive lymphomas.
Extranodal NK/T-cell lymphoma, nasal type
Pediatric-type follicular lymphoma
Indolent lymphoma
Pleomorphic T-cell lymphoma
Mature T-cell lymphoma
Primary mediastinal B-cell lymphoma
Nodular lymphocyte predominant Hodgkin lymphoma
T cell/histiocyte-rich large B-cell lymphoma