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. 2026 Jul 13;16:1809955. doi: 10.3389/fonc.2026.1809955

Figure 1.

Panel A shows a blood smear with several purple-stained white blood cells; red arrows indicate specific cells of interest. Panel B presents a similar smear with more purple-stained cells, two of which are marked by red arrows. Panel C displays another smear, with one cell highlighted by a red arrow. Panel D is a bone marrow aspirate histology section with purple-stained cellular clusters among clear fat spaces and a dashed square showing an area of interest. Panel E magnifies this boxed region, providing a closer view of the cellular architecture. Panel F is an immunohistochemistry section labeled CD20, showing brown-stained cells among clear fat spaces. Panel G is labeled CD3, highlighting different brown-stained cells. Panel H, labeled PAX5, marks a distinct population of brown-stained cells. Panel I, labeled CD138, presents another subset with scattered brown-stained cells.

Morphological and immunohistochemical findings of bone marrow involvement. (A-C) Bone marrow aspirate smears (Wright-Giemsa stain, ×1000). (A) Small lymphocytes (arrow): small, round to ovoid cells with scant pale blue cytoplasm. (B) Plasmacytoid lymphocytes (arrow): slightly larger than small lymphocytes, featuring more abundant cytoplasm and eccentric nuclei. (C) Plasma cells (arrow). (D, E) Bone marrow core biopsy (H&E stain), (D) ×200 magnification; (E) ×400 magnification, showing no discrete lymphoid aggregates. (F-I) Immunohistochemical staining of the bone marrow core biopsy (×200 magnification). (F) CD20 highlights B lymphocytes with an interstitial infiltration pattern. (G) CD3 highlights scattered T lymphocytes. (H) PAX5 shows nuclear positivity in B lymphocytes, comprising approximately 30% of nucleated cells. (I) CD138 shows plasma cells in a scattered and clustered distribution.