Demonstration of clonal immunoglobulin gene rearrangements in cutaneous B-cell lymphomas and pseudo-B-cell lymphomas: differential diagnostic and pathogenetic aspects.
Twenty-five patients with a benign or malignant cutaneous B-cell lymphoproliferative disease, including seven cutaneous pseudo-B-cell lymphomas, eight primary cutaneous B-cell lymphomas (CBCL), and 10 secondary cutaneous B-cell lymphomas, were investigated for the presence of clonal immunoglobulin (Ig) gene rearrangements using Southern blot hybridization analysis. The selection of pseudo-B-cell lymphomas was based on the presence of polyclonal light-chain expression with immunohistochemical analysis. All cases of CBCL demonstrated monotypic light-chain expression or absence of detectable Ig on CD20+ B cells. Clonal rearrangements of one or more Ig genes were demonstrated in four of seven cases of cutaneous pseudo-B-cell lymphomas, six of eight cases of primary CBCL, and in all cases of secondary CBCL. The observation that cutaneous pseudo-B-cell lymphomas as defined by immunohistochemical criteria often contain occult monoclonal B-cell populations implies that differentiating between pseudo-B-cell lymphomas and CBCL is not always possible by means of gene-rearrangement analysis. These findings may support the concept that cutaneous pseudo-B-cell lymphomas and primary CBCL are part of a continuous and progressive spectrum of B-cell lymphoproliferative skin disorders.
Rijlaarsdam
U
U
Department of Dermatology, Free University Hospital, Amsterdam, The Netherlands.
Bakels
V
V
van Oostveen
J W
JW
Gordijn
R J
RJ
Geerts
M L
ML
Meijer
C J
CJ
Willemze
R
R
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003937:Diagnosis, Differential; D005260:Female; D015322:Gene Rearrangement, B-Lymphocyte; D015326:Gene Rearrangement, B-Lymphocyte, Heavy Chain; D015328:Gene Rearrangement, B-Lymphocyte, Light Chain; D005803:Genes, Immunoglobulin / Q000235:genetics*; D006801:Humans; D016393:Lymphoma, B-Cell / Q000175:diagnosis / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D012878:Skin Neoplasms / Q000175:diagnosis / Q000235:genetics*