The authors studied 48 cases of well-differentiated lymphocytic
neoplasms using a panel of
monoclonal antibodies applied to frozen sections. Forty-seven
tumors expressed monotypic
immunoglobulin, one or more B-lineage
antigens, and Ia (
HLA-DR)
antigen. Proliferation centers expressed the T9
antigen and increased numbers of Ki-67-positive cells. One
tumor was of T-cell origin, had a cytotoxic/suppressor cell phenotype, and showed anomalous loss of
Leu-1 antigen. Immunophenotypic findings were correlated to the clinical presentation and morphologic features of each
neoplasm. Sixteen
tumors were associated with peripheral
lymphocytosis (greater than 4000/cu mm), 13 biopsies were obtained from extranodal sites, 16
tumors had proliferation centers, and 11
neoplasms had plasmacytoid features. The authors found no absolute and few statistically significant immunologic differences between the B-cell
tumors according to their clinical presentation or morphologic features.
Tumors associated with peripheral
lymphocytosis more commonly expressed the
Leu-1 antigen (P less than 0.01) and
IgD (P less than 0.01) and less frequently were stained by
BA-2 (P less than 0.05) and OKT9 (P less than 0.05). Plasmacytoid
neoplasms more frequently expressed the Tac (P less than 0.01) and T9
antigens (P less than 0.05), and all expressed kappa light chain (P less than 0.05). Extranodal
neoplasms more commonly expressed
IgM (P less than 0.01). In contrast to the markedly different clinical presentation and morphologic appearance these
tumors may have, the immunologic data suggest that B-cell small lymphocytic
neoplasms are relatively homogeneous. For an individual case, immunophenotype does not predict clinical presentation or morphologic features.