Clinical presentation and outcomes of solitary plasmacytoma in a tertiary hospital in the UK.

Solitary plasmacytoma is a rare localised neoplasm of monoclonal plasma cells. The standard treatment involves radical radiotherapy; however, a significant proportion of patients subsequently develop multiple myeloma. In this study, we evaluate the outcomes of solitary plasmacytoma in a retrospective cohort of patients treated in a single tertiary centre.The case records of plasmacytoma patients treated in a 15-year period were analysed and retrospectively followed up from the date of diagnosis. Thirty-four cases met the inclusion criteria; 27 (79%) solitary plasmacytoma of bone (SBP) and 7 (21%) extramedullary plasmacytoma (EMP). The thoracic vertebrae were the commonest sites for SBP while EMP occurred most frequently in the upper airway. Pain and spinal cord compression were the most frequent symptoms. A paraprotein was detectable in 18 (53%) patients. Over a median follow-up of 48 months, 13 (38%) developed multiple myeloma. The 5- and 10-year survival rates were 80% and 56%, respectively; median progression-free survival was 77 months. Four patients (12%) developed a second malignancy.Progression to multiple myeloma remains a formidable challenge in the management of solitary plasmacytoma, hence adjunct therapies are needed. © Royal College of Physicians 2020. All rights reserved.