case_images: PMC10657880_01
case_images: Representative bone marrow (BM) smear images after chemotherapy. (A, B) Plasmacytoid change of lymphocytes was observed occasionally in the BM smear (arrow).
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case_images: F1
case_images: Fluorine-18-fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET/CT) scan showed enlargement of the right cervical lymph node (53 mm x 34 mm) with increased metabolic activity (SUVmax 27.7) (Supplementary Figures S1A-C). Immunohistochemistry (IHC) staining demonstrated that the tumor cells were positive for CD20, CD10, IgM, and BCL-6, and partially positive for MUM-1, c-MYC (30%), and P53 (30%-40%) (Supplementary Figures S1D-K), while negative for CD3, BCL-2, MNDA, CD5, cyclinD1, CD21, CD23, and AE1/AE3. However, during the treatment and follow-up visit, serum IgM persisted elevated (Supplementary Figure S1L), while the levels of LDH and Hb were normal. The plasmacytoid change of lymphocytes was observed occasionally in the BM smear (Figures 1A, B).
case_images: Representative images of multiparameter flow cytometry analysis of the bone marrow after chemotherapy. (A-G) Two distinct subgroups of abnormal B-cell populations, which were positive for CD19. (A, H-L) One distinct subgroup of abnormal plasma cells, which was positive for CD38.
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case_images: F2
case_images: One subgroup accounted for approximately 0.24% of nuclear cells with a high side scatter (blue dots circled in Figures 2A-G), which was positive for CD19 (Figure 2A), CD10 (Figures 2B, D), CD20 (Figure 2C), CD23bri (Figure 2E), CD200part (Figure 2F), and CD43 (Figure 2F), and negative for CD22, CD38 (Figures 2A, B), FMC7 (Figure 2D), and CD5 (Figure 2E), without the expression of the cytoplasm immunoglobulin light chain (Figure 2G). Another subgroup accounted for 0.02% of nuclear cells with a low side scatter (green dots circled in Figures 2A-G), and positively expressed CD19 (Figure 2A), CD22dim, CD5 (Figure 2E), CD23 (Figure 2E), CD43 (Figure 2F), and CD200 (Figure 2F), with no expression of CD38 (Figures 2A, B), CD20 (Figure 2C), CD10 (Figures 2B, D), CD11c, and FMC7 (Figure 2D), with lambda light chain being restricted (Figure 2G). The third subgroup was an abnormal plasma cell population, which accounted for approximately 0.06% of nuclear cells (brown and purple dots circled in Figure 2A), positively expressed CD45, CD38 (Figure 2A), CD138, CD28 (Figure 2H), CD27 (Figure 2I), CD81 (Figure 2I), and CD19part (Figure 2J), and negatively expressed CD117 (Figure 2H) and CD56 (Figure 2J), with lambda light chain being restricted (Figures 2K-L).
case_images: Representative pathological staining images of bone marrow (BM) biopsy after chemotherapy and at initial diagnosis. H&E staining (400X) of the BM biopsy sample after chemotherapy (A) and prior to chemotherapy (G) showed the infiltration of lymphocytes into bone trabeculae. Immunohistochemistry staining (400X) of the BM biopsy sample after chemotherapy (B-E) and prior to treatment (H-L).
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case_images: F3
case_images: On the other hand, infiltration of lymphocytes into the bone trabeculae was observed in BM biopsy (Figure 3A), and immunohistochemical (IHC) staining showed that the plasmacytoid cells accounted for approximately 5% of nuclear cells and were lambda-restricted. In detail, those cells were positive for IgM (Figure 3B), CD138 (Figure 3C), kappa (Figure 3D), lambda (Figure 3E), Ki-67, and CD10, and partially positive for CD19, CD3, CD34, CD117, TDT, BCL2, and BCL6, while negative for CD20 (Figure 3F), MUM-1, and c-MYC. Lymphocytes also infiltrated into the bone trabeculae (Figure 3G). The plasmacytoid cells accounted for approximately 5% of nuclear cells, which were positive for IgM (Figure 3H), CD138 (Figure 3I), kappa (Figure 3J), lambda (Figure 3K), CD20 (Figure 3L), PAX-5, and CD38, and negative for cyclinD1, CD56, CD117, CD3, and CD19 by IHC staining. One of the clones (IGHV 3-11*06/IGHJ 3*02) might be related to DLBCL whereas another (IGHV 3-11*06/IGHJ 6*02) might be related to WM (Supplementary Figure S3), which probably attributed to the persisted elevation of the serum IgM level post-treatment.