Composite lymphomas may include:
(1) Hodgkin’s disease and a non-Hodgkin’s lymphoma
(2) B-cell and T-cell non-Hodgkin’s lymphoma
(3) 2 distinct types of B-cell lymphoma
(4) 2 distinct types of T-cell lymphomas
The 2 types of lymphoid neoplasms should be morphologically and phenotypically different.
The presence of 2 low-grade B-cell lymphomas may indicate biclonal lymphomas (Boiocchi et al)..
Differential diagnosis:
(1) Richter’s syndrome (second, more aggressive lymphoma arising in a patient with a pre-existing lymphoma)
(2) progression of lymphoma to a higher grade over time
The prognosis depends on the more unfavorable component so this should be the primary target for therapy.
