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

Relative frequencies

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