PMC8531735_01
Anaplastic large cell lymphoma, giant cell-rich, tumor nodule comprised of sheets of large neoplastic cells with scattered giant cells in a background of mixed inflammatory cells. An atrophic mammary duct and lobule is present in the left upper corner (H and E stain, original magnification x40)
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F1
Microscopic sections showed a nodular infiltrate comprised of discohesive large-giant highly atypical round tumor cells with ample eosinophilic to amphophilic cytoplasm [Figure 1].
Various patterns of tumor cells are evident including hallmark cells, mononucleated, binucleated, and multinucleated giant tumor cells. (H and E stain, original magnification x200)
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F2
There was a striking nuclear pleomorphism with mono-nucleated, bi-nucleated, multinucleated, and multilobated forms [Figure 2].
(a and b) Several hallmark cells and multinucleated giant cells with scattered mitotic figures (H and E stain, original magnification x200)
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F3
A significant proportion of tumor cells exhibited eccentric, horseshoe-or kidney-shaped nuclei "hallmark cells" [Figure 3a and b].
A multinucleated tumor giant cell, scattered mononuclear cells, and an atypical mitotic figure is evident in this field (H and E stain, original magnification x400)
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F4
Brisk mitotic activity was noted with frequent atypical mitotic figures [Figure 4].
Immunohistochemical stain for CD30 shows diffuse strong immunoreactivity on the cell membrane and in the Golgi region (original magnification x200)
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F5
Immunohistochemistry, tumor cells showed uniform strong and homogenous immunoreactivity for CD30 on the cell membrane and in the Golgi region [Figure 5].
Immunohistochemical stain for CD45 (LCA) shows diffuse membranous staining (original magnification x200)
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F6
Strong positivity for CD45 (Leukocyte Common Antigen, LCA) [Figure 6], CD45RO, granzyme B, TIA-1, and vimentin was seen.
Immunohistochemical stain for CD4 shows diffuse membranous staining of tumor cells (original magnification x200)
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F7
Focal expression of CD4 [Figure 7], CD43, EMA, BCL-6, and BCL-2 was noted.