Plasmacytoma is a clonal proliferative disorder of neoplastic plasma cells and is biologically malignant 1) growing within soft tissue or within the axial skeleton.
The most common spinal manifestation of plasmocytoma is involvement of the vertebral bodies leading to extradural compression of the cord. Only rarely plasmocytoma manifests itself as a primarily dural lesion leading to an intradural cord compression.
There are three distinct groups of plasmacytoma defined by the International Myeloma Working Group:
Solitary bone plasmacytoma (SBP), extramedullary plasmacytoma (EP), and multiple solitary plasmacytomas that are either primary or recurrent. Among the three, SPB is the most common and occurs as lytic lesions within the axial skeleton 2).
Plasmacytoma is rare that responsible for only 5% of plasma cell neoplasms.
Due to their cellular similarity, plasmacytomas have to be differentiated from multiple myeloma. For SPB and EP the distinction is the presence of only one lesion (either in bone or soft tissue), normal bone marrow (<5% plasma cells), normal skeletal survey, absent or low paraprotein and no end organ damage.