TY - JOUR
T1 - Cutaneous B-cell lymphoma with loss of CD20 immunoreactivity after rituximab therapy
AU - Clarke, Loren E.
AU - Bayerl, Michael G.
AU - Ehmann, W. Christopher
AU - Helm, Klaus F.
PY - 2003/8
Y1 - 2003/8
N2 - Background: Antibodies to the B-cell-specific antigen CD20 are widely used for immunohistochemical identification of B-cell lymphomas, approximately 95% of which are strongly CD20-positive. Methods: We report a 51-year-old male with a CD20-positive systemic B-cell lymphoma who developed a CD20-negative relapse with secondary cutaneous involvement after therapy with the anti-CD20 monoclonal antibody rituximab (Rituxan). Results: Biopsy of a skin nodule demonstrated an atypical lymphocytic infiltrate that was negative for CD20, CD3, lysozyme, and myeloperoxidase, but strongly positive for CD45rb (LCA) and the B-cell marker CD79a. Conclusions: We conclude that loss of CD20 expression in cutaneous B-cell lymphoma (both primary and secondary) is important to recognize, that immunohistochemistry for CD79a, another widely expressed B-cell marker, is useful in the identification of CD20-negative B cells in such cases, and that loss of CD20 expression may become more common, as use of rituximab is expected to increase.
AB - Background: Antibodies to the B-cell-specific antigen CD20 are widely used for immunohistochemical identification of B-cell lymphomas, approximately 95% of which are strongly CD20-positive. Methods: We report a 51-year-old male with a CD20-positive systemic B-cell lymphoma who developed a CD20-negative relapse with secondary cutaneous involvement after therapy with the anti-CD20 monoclonal antibody rituximab (Rituxan). Results: Biopsy of a skin nodule demonstrated an atypical lymphocytic infiltrate that was negative for CD20, CD3, lysozyme, and myeloperoxidase, but strongly positive for CD45rb (LCA) and the B-cell marker CD79a. Conclusions: We conclude that loss of CD20 expression in cutaneous B-cell lymphoma (both primary and secondary) is important to recognize, that immunohistochemistry for CD79a, another widely expressed B-cell marker, is useful in the identification of CD20-negative B cells in such cases, and that loss of CD20 expression may become more common, as use of rituximab is expected to increase.
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U2 - 10.1034/j.1600-0560.2003.00078.x
DO - 10.1034/j.1600-0560.2003.00078.x
M3 - Article
C2 - 12859745
AN - SCOPUS:0043168018
SN - 0303-6987
VL - 30
SP - 459
EP - 462
JO - Journal of Cutaneous Pathology
JF - Journal of Cutaneous Pathology
IS - 7
ER -