Background: The coexistence of cutaneous T-cell lymphoma (CTCL) and a
B-cell malignancy (BCM) is rare. Objective: Our aim was to assess the
clinical and pathologic aspects of coexistent CTCL and BCM and to exam
ine potential explanations for this association. Methods: We report si
x cases of concurrent CTCL and BCM in which B- and T-cell lineages wer
e demonstrated by immunologic studies. The literature includes 13 addi
tional cases. All 19 CTCL-BCM cases are reviewed. Results: CTCL either
preceded or followed the BCM, which was a low-grade malignancy in mos
t cases (16 of 19). Possible explanations for the association include
a genetic predisposition, underlying viral infection, chemotherapy-ind
uced carcinogenesis, stimulation of a B-cell clone by malignant helper
T cells, and alterations in progenitor cells before determination of
B- and T-cell lineage. Conclusion: An alteration in progenitor cells,
with subsequent oncogenic activation of variable origin, might account
for most cases of coexistent CTCL and BCM.