Mature T-cell and natural killer (NK) cell neoplasms
T-cells and NK-cells are derived from a common precursor1, are closely related functionally and immunophenotypically and therefore their neoplasms are classified together. They account for about 10-12% of all non-Hodgkin lymphomas. There are relatively high prevalences of T-cell lymphomas in Japan and the Caribbean due to endemic HTLV-1 infection. Nasal NK/T-cell lymphoma is much more common in Asians and native Americans.
Classification is based on all available evidence to define disease entities. There is great morphological diversity and lack specific immunophenotypes; clinical features assume a great importance. Most cytotoxic T-cell and NK-cell lymphomas are extra-nodal1. There is often extensive apoptosis and necrosis1, in part due to cytolytic proteins, in part due to the propensity for vascular invasion.
Demonstration of clonality requires molecular examination of the T-cell receptor for gene rearrangement.
Mature T cell lymphomas are listed according to their major clinical presentation:
-
-
leukaemic / disseminated
- T-cell prolymphocytic leukaemia
- T-cell large granular lymphocytic leukaemia
- aggressive NK cell leukaemia
- adult T-cell leukaemia/lymphoma
cutaneous
-
mycosis fungoides
Sézary syndrome
Primary cutaneous anaplastic large cell lymphoma
lymphomatoid papulosis
other extranodal
-
extranodal NK/T cell lymphoma, nasal type
enteropathy-type T-cell lymphoma
hepatosplenic T-cell lymphoma
subcutaneous panniculitis-like T-cell lymphoma
- nodal
- angioimmmunoblastic T-cell lymphoma
- peripheral T-cell lymphoma, unspecified
- anaplastic large cell lymphoma
-
- of uncertain lineage
- blastic NK cell lymphoma
References
World Health Organization Classification of Tumours, Tumours of the haematopoietic and lymphoid tissues, IARC Press 2001.
1 VE Nava and ES Jaffe. The pathology of NK-cell lymphomas and leukamias. Adv Anat Pathol 2005;12:27-34.
This page last revised 23.3.2005.
©SMUHT/PW Bishop