Plasmacytoma – Dr. Darrel White
Solitary plasmacytoma is relatively uncommon, occurring in approximately 5% of plasma cell dycrasias. According to the 2014 IMWG, solitary plasmacytoma is defined with no vs. minimal marrow involvement. The rate of progression with skeletal series is noted to be high - visibility requires 30-50% trabecular bone loss. There are several ways that plasmacytomas can be detected: MRI of the spine and pelvis, whole body MRI, low dose WBCT or PET/CT
Treatment protocol is moderate dose involved field radiation. Unfortunately, systemic treatment does not appear to provide an advantage. The goals of therapy include long term remission and potential cure– most likely with soft tissue plasmacytoma and solitary plasmacytoma without marrow involvement. Complete response is important and includes normalization of M-protein and marrow; free light chain assay is also important in terms of long-term follow-up. Extramedullary plasmacytoma in the setting of myeloma is distinct and is associated with high risk disease and a poor prognosis. This entity is increasingly common in relapsed/refractory myeloma as patients live longer and are exposed to more lines of therapy.