Histiocytic Sarcoma - Immunostains: CD163
Immunohistochemical Profile of Histiocytic Sarcoma: As expected, histiocytic markers are positive. They include CD68 (somewhat non-specific), CD163 (more specific; shown here), CD14, CD4, CD11c, lysozyme (granular pattern with accentuation around Golgi region), and alpha1-antitrypsin. In addition, there is immunoreactivity for CD45, CD45RO, and HLA-DR. S100 protein, CD56, and CD15 may be weakly positive. Ki-67 labeling index varies from 10% to 90% of tumor cells. Negative markers:: B- and T-lineage specific markers; follicular dendritic cell markers (CD21, CD23, CD35); Langerhans cells (langerin, CD1a); CD34, CD30, HMB-45, myeloperoxidase, EMA, and cytokeratins. Image courtesy of: Miguel Reyes Mugica, MD, Chief of Pediatric Pathology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA; used with permission.