Subcutaneous (panniculitis-like) T-cell lymphoma, STCL

Definition

A cytotoxic T-cell lymphoma involving subcutaneous tissue, composed of tumour cells of varying size and often showing marked necrosis and karyorrhexis.

Synonyms

Epidemiology

Rare, representing <1% of all non-Hodgkin lymphomas. There is a broad age range, which includes children.

Clinical features

Presentation is with multiple tender skin-coloured or erythematous subcutaneous nodules, most often on the lower extremities. Large nodules may be necrotic. Some patients develop a haemophagocytic syndrome, pancytopenia, fever, myalgia and hepatosplenomegaly. There is not usually lymphadenopathy.

Histopathology

At an early stage, the infiltrate may appear deceptively benign. The infiltrate extends throughout the subcutis. Neoplastic cells range from small with round nuclei to large with hyperchromatic nuclei. Rimming of fat cells by the neoplastic cells is characteristic. A reactive histiocytic component is common, with vacuolation of the histiocytes due to ingestion of lipid. Conspicuous mitoses, vascular invasion, karyorrhexis and necrosis may be seen. The dermis is usually spared, except in gd-positive cases. Phagocytosis of erythrocytes be non-neoplastic macrophages is a harbinger of the haemophagocytic syndrome1. Angioinvasion and destruction are associated with an NK immunophenotype1.

Immunohistochemistry

 

CD1a

   

CD2

positive1

CD3

positive

CD4

negative, except in CD4+ variants1

CD5

 

CD7

 

CD8

usually positive, unless gd-positive

CD11b

 

CD16

 

CD20

negative1

CD25

positive in 60% of cases1

CD30

positive in 40% of cases1

CD43

positive1

CD45

positive1

CD45RO

positive1

CD56

positive if gd-positive

CD57

negative except in NK variant1

TdT

 

TIA-1

usually positive1

granzyme B

usually positive

perforin

usually positive1

TCR

most usually ab-positive, 25% gd-positive, negative in rare NK variant1

ALK

 

EBV

negative in most cases1

 

CD4-/CD8- variants occur1.

Differential diagnosis

Prognosis

Most cases are naturally aggressive, but responsive to chemotherapy. A minority are indolent1. Haemophagocytic syndrome is associated with a poor prognosis2.

References

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

1Liu, V. and McKee, P.H. Cutaneous T-cell lymphoproliferative disorders: approach for the surgical pathologist: recent advances and clarification of confused issues. Adv Anat Pathol 2002;9:79-100.

2Gonzalez, C.L., Medeiros, L.J., Braziel, R.M. and Jaffe, E.S. T-cell lymphoma involving subcutaneous tissue. A clinicopathologic entity commonly associated with hemophagocytic syndrome. Am J Surg Pathol 1991;15:17-27.

This page last revised 19.12.2002.

©SMUHT/PW Bishop