PMC6767481_01
PET-CT scan (at diagnosis). The PET-CT scan revealed systemic swollen lymph nodes, some of which were FDG-avid. The left ischium had a small high-density area with high FDG-avidity. A diagnosis of lymphoma is suspected.
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Positron emission tomography-computed tomography (PET-CT) scan indicated a dubious diagnosis of lymphoma (Figure 1).
Flow cytometry and cytogenetic results of bone marrow at the time of initial diagnosis. (A) Flow cytometry of bone marrow found B cells with abnormal immunophenotype, which expressed CD19, CD200, cLambda, CD10, CD20 and CD79b, not expressing CD5, CD103 and FMC7. The signals of forward scatter and side scatter indicated a small cell size of the abnormal B cells. (B) R-banding technique revealed a normal karyotype: 46, XY[14].
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The bone marrow aspiration was performed and flow cytometry of the bone marrow revealed B cells with abnormal immunophenotype, which indicated follicular lymphoma invasion to the bone marrow (Figure 2A). Genetic testing revealed a normal karyotype: 46, XY (Figure 2B).
Serum IgM level before and after therapies. (A) The serum IgM level was 23.4g/L before R-CHOP regimen and 23.90g/L after 4 cycles of R-CHOP regimen. (B) The serum IgM level was 23.90g/L before R-Vd regimen and 16.10g/L after 2 cycles of R-Vd regimen.
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An abnormal elevation of IgM serum concentration was observed both before and after R-CHOP (IgM serum concentration was above 23g/L, Figure 3A). After 2 cycles of R-Vd regimen, serum IgM concentration significantly decreased (Figure 3B).
Immunofixation of peripheral blood and MYD88 L265P mutation status of bone marrow. (A) An immunofixation of peripheral blood confirmed the existence of monoclonal IgM and lambda light chain in the blood. (B) A MYD88 L265P somatic mutation was confirmed by a conventional allele-specific polymerase chain reaction. The left lane showed the patient's sample, the middle lane positive control sample, and the right lane negative control sample.
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The serum immunofixation test was performed, that showed the existence of monoclonal IgM and lambda light chain in the blood (Figure 4A). An MYD88 L265P somatic mutation of the bone marrow was indicated by polymerase chain reaction (PCR) (Figure 4B).
Histopathological sections of the lymph nodes (hematoxylin and eosin staining). Small atypical lymphocytes diffusely or follicle-like distributed and follicle-like structure accounted for 75% of the whole tissue. The absolute number of centroblasts was 0-5 for each high-power field. (A) original magnification: 50x; (B) original magnification: 100x; (C) original magnification: 200x; (D) original magnification: 400x.
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The absolute number of centroblasts was 0-5 for each high-power field (Figure 5).
Immunohistochemical staining of the lymph nodes. The tumor cells were positive for (A) CD20 (original magnification: 400x); (B) CD23 (original magnification: 400x); (C) CD10 (original magnification: 400x); (D) Bcl-2 (original magnification: 400x); (E) Ki-67 (with a proliferation index approximately 5-10%; original magnification: 400x). The tumor cells were negative for CD3, CD5, and Cycline-D1 (data not shown).
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In addition, the follicular dendritic cell (FDC) network stained with CD23 showed that 5-10% of tumor cells were positively associated with Ki-67 (Figure 6).