Splenic angiosarcoma metastasis to small bowel presented with gastrointestinal bleeding

Figure 4 A: Photomicrography of the spleen reveals neoplastic sinusoidal endothelial cells with marked cytological atypia (arrowhead) lining the congested sinusoid spaces (hematoxylin and eosin staining, 200×); B: immunohistochemical staining of the neoplastic cells is positive for factor XIII associated antigen (immunostain, 200×); C: histological examination of the specimen of small intestine shows metastatic neoplastic cells primarily distributed within the submucosal layer and focally extending to the mucosal layer (hematoxylin and eosin staining, 100×); D: photomicrography of the intestinal vessel reveals presence of individual neoplastic cells (arrowhead) within the vascular lumen (hematoxylin and eosin staining, 400×).