CD138 (Syndecan-1) is expressed in mesenchymal and epithelial cells. In the bone marrow hematopoietic cells, CD138 is a specific (and sensitive) marker for plasma cells (e.g. multiple myeloma). The biggest pitfall in utilization of CD138 is plasmacytoid neoplasms showing expression of CD138 without consideration of a non-hematopoietic neoplasm expressing CD138!! Always consider a metastatic process in the bone marrow, and utilize additional markers (AE1/AE3, kappa/lambda) to exclude/prove plasma cells origin.
The majority of epithelial neoplasms express CD138, and even a significant number of osteosarcomas, osteoid osteomas, and osteoblastomas react with CD138. Recent literature suggests CD138 to be an adverse prognostic indicator in advanced and nonluminal subtype breast carcinomas.
Photomicrographs
![CD138 - Bone Marrow](https://www.pathmd.com/wordpress/wp-content/uploads/2017/10/CD138-1024x682.jpg)
![CD138-Ki67 - Bone Marrow](https://www.pathmd.com/wordpress/wp-content/uploads/2017/10/CD138-Ki67_2-1024x680.jpg)
![CD138 - Bone Marrow](https://www.pathmd.com/wordpress/wp-content/uploads/2017/10/CD138_5-1024x682.jpg)
![CD138 - Benign Plasma Cells](https://www.pathmd.com/wordpress/wp-content/uploads/2017/08/CD138_B9_PCs-1-1024x768.jpeg)
References
Bone Marrow IHC. Torlakovic, EE, et. al. American Society for Clinical Pathology Pathology Press © 2009. pp. 134.
Nunez, A. L., Siegal, G. P., Reddy, V. V. B., & Wei, S. (2012). CD138 (syndecan-1) expression in bone-forming tumors. American Journal of Clinical Pathology, 137(3), 423–428. doi:10.1309/AJCP6V4YPFBOCYXG
Nguyen, T. L., Grizzle, W. E., Zhang, K., Hameed, O., Siegal, G. P., & Wei, S. (2013). Syndecan-1 overexpression is associated with nonluminal subtypes and poor prognosis in advanced breast cancer. American Journal of Clinical Pathology, 140(4), 468–474. doi:10.1309/AJCPZ1D8CALHDXCJ
Joshi, R., Horncastle, D., Elderfield, K., Lampert, I., Rahemtulla, A., & Naresh, K. N. (2008). Bone marrow trephine combined with immunohistochemistry is superior to bone marrow aspirate in follow-up of myeloma patients. Journal of Clinical Pathology, 61(2), 213–216. doi:10.1136/jcp.2007.049130