Figure 1: H&E images
Low power photomicrographs reveal a well demarcated tumor within the red pulp and uninvolved spleen at the periphery. Tumor shows proliferation of anastomosing vascular channels interspersed with dilated vascular and cyst like spaces.
Figure 2: H&E images
As noted on medium power photomicrograph (Image on the left), vascular channels have irregular lumina with focal papillary projections. High power photomicrograph (Image on the right) reveals vascular channels that are lined by tall and plump, bland-looking cells, some of which are seen projecting and sloughing into the lumina. Cytologic atypia is not evident.
Figure 3: CD31 and ERG (Ets-related gene)
Both CD31 (Image on the left) and ERG (Image on the right) are endothelial markers and typically stain the sinus lining cells in LCA, as expected.
Figure 4: CD8
CD8 expression by normal sinus lining (littoral) cells highlights the architectural framework of the red pulp. Note the negative CD8 staining in sinus lining cells of LCA, while, normal splenic sinuses at the periphery of lesion are positive for CD8.
Figure 5: CD34
Endothelium of peripheral splenic vessels are highlighted by CD34 (bottom left of image), and the lining tumor cells of anastomosing channels (top right of image). However the expression of CD34 in this case in the lesional endothelium is unusual for LCAs.
Figure 6: CD68
Antibody to CD68 demonstrates dual staining of the sinus lining littoral cells and macrophages within the vessel lumina.
Figure 7: Langerin
Langerin can be seen highlighting the sinus lining cells in LCA. Whether this represents true CD207 expression or cross-reactivity is still uncertain.
Figure 8: CD21
CD21 expression (a marker of follicular dendritic cells) by the sinus lining cells of LCA is very focal in this case.
