Extranodal NK/T Cell Lymphoma, Nasal Type
Differential Diagnosis
- Nonspecific inflammatory process
- Peripheral T cell lymphoma
- Enteropathy type T cell lymphoma
- Lymphomatoid granulomatosis
- Aggressive NK cell leukemia
Nonspecific Inflammatory Process vs. Extranodal NK/T Cell Lymphoma
- Identification of aytypical cells with the following phenotypes establishes the diagnosis of nasal type NK/T lymphoma
- CD56+, EBV+, CD3+ or
- CD56-, EBV+, CD3+ and cytotoxic protein+
- Infiltration of bony trabeculae of nasal septum is highly suggestive of malignancy
Peripheral T Cell Lymphoma vs. Extranodal NK/T Cell Lymphoma, Nasal Type
- Identification of aytypical cells with the following phenotypes establishes the diagnosis of nasal type NK/T lymphoma
- CD56+, EBV+, CD3+ or
- CD56-, EBV+, CD3+ and cytotoxic protein+
| Extranodal NK/T Cell Lymphoma | Enteropathy Type T Cell Lymphoma |
|---|---|
| CD56 100% | CD56 20% |
| EBV 100% in nasal sites but variable in other sites and outside endemic areas | EBV variable, possibly by geography |
| No adjacent enteropathy | Adjacent enteropathy 75% |
Lymphomatoid Granulomatosis vs. Extranodal NK/T Cell Lymphoma
- Lymphomatoid granulomatosis was originally considered an angiocentric T cell lymphoma
- It is now recognized as an EBV+ B cell process with a marked T cell response
- Cases involving bone marrow overlap with aggressive NK cell leukemia, which may represent the leukemic counterpart of this lymphoma
