IntroductionPCL is a rare and aggressive variant of multiple myeloma (MM), distinguished by the presence of circulating plasma cells in the peripheral blood. A diagnosis of PCL is previously was 20 % but currently can be confirmed when there are at least 5% plasma cells present in the peripheral blood or an absolute plasma cell count of 2000/µl. However, the morphological characteristics of plasma cells can sometimes resemble those of myeloblasts under microscopic examination, which can make it difficult to differentiate between the two cell types. PCL is considered primary when it presents at initial diagnosis and secondary when it occurs in patients with pre-existing MM. Primary PCL accounts for 60–70% of all PCL; the secondary PCL rate is 30–40%.1The diagnostic approach and treatment of PCL is similar to that of MM, but the survival of PCL remains inferior despite novel therapies and stem cell transplantation.
