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
- other
extranodal
- 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.
1VE 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