There is diffuse effacement of the nodal architecture by sheets of small lymphocytes, with or without histiocytes. Some authors argue that the presence of considerable numbers of histiocytes (which may or may not be of epithelioid type) and scarcity of reactive B cells is a prerequisite for recognising a clinically relevant entity3.
The neoplastic B cells are large and atypical but scattered and obscured by the non-neoplastic component: they constitute less than 10% of the cells4. The large cells may resemble L&H cells, Reed-Sternberg cells, centroblasts or immunoblasts9.
The T-cells do NOT form rosettes around the neoplastic cells.
There is often fine reticular fibrosis. THRLBCL may occasionally be angiocentric and angiodestructive10.
Variant
|
|
T-cell rich B-cell lymphoma |
|||
neoplastic cells
|
positive1, positive9 |
positive1 |
negative1 |
||
positive1, with rare exceptions10,30/309 |
positive1, with rare exceptions10 |
||||
positive1, 10/179 |
variably positive1,10 |
usually negative1 |
|||
CD3 |
negative1 |
negative1 |
|||
variable1 |
positive1 |
||||
negative1, 1/309 |
negative1 |
positive1 |
|||
usually negative1, 8/309 |
negative1/weakly positive in some instances10 |
positive1 |
|||
variable: 6/101, 10/299 |
usually positive1 |
usually negative1 |
|||
negative or focal1, 3/229 |
|
|
|||
positive1, 26/299 |
positive10 |
negative10 |
|||
usually negative1, 3/299 |
|
|
|||
positive10 |
positive10 |
negative10 |
|||
positive, usually overexpressed10 |
positive, usually overexpressed10 |
rare10 |
|||
negative in the few cases tested10 |
positive10 |
negative10 |
|||
MIB1 |
most cells1, >90%of tumour cells9 |
|
|
||
usually negative1 |
negative1 |
variably positive1 |
|||
non-neoplastic cells |
usually <5% of cells1,2 |
most cells positive1 |
few cells positive1 |
||
most cells positive1 |
scattered cells1 |
scattered cells1 |
|||
negative1 |
positive1 |
negative1 |
|||
positive1 |
usually <5% of cells1 |
positive1 |
|||
CD68+ histiocytes |
variable10 |
some10 |
variable10 |
||
negative1 |
positive1 |
positive1 |
|||
IgH gene rearrangement |
monoclonal1 |
polyclonal1 |
|||
Hodgkin's disease, lymphocyte predominance The presence of significant numbers of small B lymphocytes, especially if there is a vaguely nodular growth patter, raises this diagnosis.
T-cell lymphoma. It is necessary to identify the scattered neoplastic B-cells to avoid this mistaken diagnosis.
If angiocentric and angio-destructive, may resemble lymphomatoid granulomatosis.
A high mortality was reported initially5,6, although others have not found it any worse than DLBCL7,8.
References
World Health Organization Classification of Tumours, Tumours of the haematopoietic and lymphoid tissues, IARC Press 2001.
4World Health Organization Classification of Tumours, Tumours of the haematopoietic and lymphoid tissues, IARC Press 2001.
This page last revised 19.1.2003.
©SMUHT/PW Bishop