Peripheral T cell lymphoma, unspecified, PTL, unspec

Definition

Those peripheral T-cell lymphomas which cannot currently be otherwise classified.

Synonyms

Epidemiology

50% of all peripheral T-cell lymphomas

Clinical features

Present with nodal disease, generalised disease or leukaemia.

Histopathology

The histology is variable, the neoplastic infiltrate consisting of medium or large cells, clear cells or Reed-Sternberg-like cells. High endothelial venules are usually prominent. There may be a mixed inflammatory component.

Variants:

• T-zone with preservation, or hyperplasia, of follicles.

• Lymphoepithelial cells may be abundant (Lennert's lymphoma under the Kiel classification).

Immunohistochemistry

†: fresh frozen tissue only

Differential diagnosis

• PTL, unspec: CD4>CD8, frequently CD7-, CD5-, CD30 variable

• AILT: mixed CD4/CD8, numerous FDCs, EBV+ blasts

• ATLL: CD4+, CD25+, CD7-, CD30 variable, CD15 variable

• ALCL: CD30+, ALK usually positive, EMA+

• THRLBCL: large CD20+ blasts, reactive T-cells

• atypical T-zone hyperplasia; distinction from T-zone variant of PTL requires molecular analysis.

Prognosis

Usually poor.

References

World Health Organization Classification of Tumours, Tumours of the haematopoietic and lymphoid tissues, IARC Press 2001.

This page last revised 23.12.2002.

©SMUHT/PW Bishop