Tanioka Fumihiko, Tamashima Sadahiro, Shimizu Shin-ichi, Kobayashi Hiroshi, Kobayashi Yukio, Sugimura Haruhiko
Division of Pathology and Laboratory Medicine, Iwata City Hospital, Iwata, Shizuoka, Japan.
Jpn J Clin Oncol. 2003 May;33(5):232-7. doi: 10.1093/jjco/hyg043.
A case of primary plasma cell leukemia with hairy-cell morphology and lambda-type Bence-Jones protein is reported. Most of the atypical cells in the peripheral blood of this case were small lymphoid cells or lymphoplasmacytoid lymphocytes with numerous cytoplasmic hairy projections. Plasmablastic cells and 'tadpole'-like cells were also present in the bone marrow. Immunohistochemically, these atypical cells expressed the cytoplasmic lambda light chain and surface CD38 proteins but were negative for B-cell markers such as CD19, CD20 and CD79a. VLA-5 (CD49e), which is supposed to be expressed in mature populations of plasma cells, was negative. A sequence analysis of the variable region gene in the light-chain (V(L)) and heavy-chain (V(H)) loci of immunoglobulin demonstrated significant somatic hypermutation and intraclonal nucleic acid sequence variations. To our knowledge, the intraclonal diversity of these loci has been previously reported in some cases of monoclonal gammopathy of undetermined significance (MGUS), but never in a case of multiple myeloma. The immunohistochemical and molecular characteristics of this case allowed us to delineate the origin of the leukemic cells with hairy cell-morphology as germinal center B-cells, which would be at a more immature stage than the presumable origin of multiple myeloma.
报告了一例具有毛细胞形态和λ型本斯-琼斯蛋白的原发性浆细胞白血病病例。该病例外周血中的大多数非典型细胞为小淋巴细胞或淋巴浆细胞样淋巴细胞，伴有大量胞质毛状突起。骨髓中也存在浆母细胞和“蝌蚪”样细胞。免疫组化显示，这些非典型细胞表达胞质λ轻链和表面CD38蛋白，但对B细胞标志物如CD19、CD20和CD79a呈阴性。假定在成熟浆细胞群体中表达的VLA-5（CD49e）为阴性。对免疫球蛋白轻链（V(L)）和重链（V(H)）基因座可变区基因的序列分析显示存在显著的体细胞超突变和克隆内核酸序列变异。据我们所知，这些基因座的克隆内多样性此前在一些意义未明的单克隆丙种球蛋白病（MGUS）病例中有报道，但在多发性骨髓瘤病例中从未有过报道。该病例的免疫组化和分子特征使我们能够将具有毛细胞形态的白血病细胞起源确定为生发中心B细胞，其阶段比多发性骨髓瘤的假定起源更不成熟。
