case_images: PMC10564572_01
case_images: CT scan identified no significant lymphadenopathy but revealed numerous subcutaneous soft tissue nodules throughout the (a) chest and (b) abdominal wall. (c) A low-attenuation hepatic lesion within segment VII of the liver. (d) A sagittal and transverse view of maxillary sinuses shows bilateral mucosal thickening and focal erosion of the anterior wall of the left maxillary sinus with extrasinusoidal extension into the overlying soft tissue. Note: red arrows indicate relevant findings.
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case_images: fig1
case_images: Computed tomography including the head, neck, chest, abdomen, and pelvis revealed disseminated indeterminate subcutaneous soft tissue nodules and a low-attenuation hepatic lesion (Figure 1). TdT revealed strong and uniform staining for CD20 (Figure 2(c)), CD45, CD5 (Figure 2(d)), BCL2, BCL6 (Figure 2(e)), MUM1/IRF4 (Figure 2(f)), and PAX5. The cells were negative for all other markers (Figures 2(g) and 2(h)).
case_images: Deep portion of cutaneous bunch biopsy. (a, b) Loose aggregates of large malignant hematolymphoid cells within subcutaneous adipose tissue (H&E, x100 and x400). The malignant cells show strong immunoreactivity for (c) CD20, (d) CD5, (e) BCL6, and (f) MUM1 and were negative for (g) CyclinD1 and (h) TdT (DAB with hematoxylin counterstain, x400).
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case_images: fig2
case_images: However, there was a focal aggregate of large atypical hematolymphoid cells within one fragment of deep adipose tissue (Figures 2(a) and 2(b)). TdT revealed strong and uniform staining for CD20 (Figure 2(c)), CD45, CD5 (Figure 2(d)), BCL2, BCL6 (Figure 2(e)), MUM1/IRF4 (Figure 2(f)), and PAX5. The cells were negative for all other markers (Figures 2(g) and 2(h)).
case_images: Maxillary sinus biopsy. (a) Dense mucosal and submucosal infiltrates of malignant hematolymphoid cells which extend to underlying bone (inset and white arrow) (H&E, x100). (b) Involvement and destruction of adnexal structures (H&E, x400). (c) The malignant cells show strong CD20 immunoreactivity (DAB with hematoxylin counterstain, x400).
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case_images: fig3
case_images: An identical population of malignant cells was found to be infiltrating separately submitted fragments of the sinus mucosa (Figure 3).
case_images: Bone marrow biopsy. (a, b) Bone marrow aspirates showing rare scattered atypical hematolymphoid cells (white arrow) with large nuclei and prominent nucleoli (Wright-Giemsa, x200 and x400). (c, d) Bone marrow core biopsy demonstrating loose lymphoid aggregates (H&E, x100 and x400) highlighted by (e) strong CD20 immunoreactivity (DAB with hematoxylin counterstain, x400).
case_images: CRIPA2023-2960965.004.jpg
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case_images: fig4
case_images: Bone marrow aspirate revealed scattered large atypical hematolymphoid cells in a background of otherwise morphologically normal trilineage hematopoiesis (Figures 4(a) and 4(b)). The bone marrow core biopsy confirmed loose aggregates of large atypical lymphoid cells with strong CD20 immunoreactivity (Figures 4(c)-4(e)).
case_images: Two distinct populations of abnormal B-cells were identified on flow cytometric evaluation of the bone marrow. (a) One population of lambda light chain-restricted CD5-positive B-cells, which appear large on forward scatter, representing the malignant lymphocytes of DLBCL NOS (highlighted in red). (b) A second incidental population of uncertain significance composed of kappa light chain-restricted CD5-positive B-cells that appear of similar size as background lymphocytes by forward scatter and show dim expression of light chain and CD20 (highlighted in red).
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case_images: fig5
case_images: Interestingly, concurrent flow cytometry of bone marrow revealed two distinct abnormal B-cell populations: (1) a population of large lambda light chain-restricted CD5-positive B-cells, consistent with the atypical lymphoid cells noted in the aspirate (Figure 5(a)), and (2) a unique population of kappa light chain-restricted CD5-positive B-cells with a CD20-dim, light chain-dim, CD23-positive, CD200-positive immunophenotype diagnostic of chronic lymphocytic leukemia (CLL) (Figure 5(b)).