Blood-filled core and delicate septa. (A) Microscopic view of the primary ileal tumor, composed of rounded nests of closely packed, monomorphous cells (EE, 10×). (B) The same architectural pattern of the hepatic metastasis, with the central, blood-filled core of blood and delicate septa of tumoral cells (EE; 10x). (C-D) Granular, cytoplasmic immunostaining for serotonin in both primary and metastatic tumors (20×).
Fiori et al. Diagnostic Pathology 2013 8:148 doi:10.1186/1746-1596-8-148