Extramedullary Plasmacytoma: Long-Term Clinical Outcomes in a Single-Center in China and Literature Review

The aim is to analyze the clinical outcomes of patients with extramedullary plasmacytoma (EMP) and review the characteristics of this disease. We retrospectively reviewed the clinical data of a cohort of 22 patients diagnosed with EMP between 1983 and 2017. Baseline characteristics and progression data were collected to calculate the incidence of progression to multiple myeloma (MM) and to analyze survival rates and outcomes. Previous major cohort studies were reviewed and compared with this study. Extramedullary plasmacytomas were located in the head and neck in 17 (77%) of the 22 patients. The median time between onset and diagnosis was 7 months, and the median age at diagnosis was 52.5 years (range 15-72 years). Extramedullary plasmacytoma occurred more frequently in men with an approximate ratio of 2.1:1. The majority of patients underwent surgery (13/22, 59.1%) and half received radiation (11/22, 50%). A small proportion of patients received chemotherapy (2/22, 9.1%). There was a median follow-up time of 98.5 months. The 5-year overall survival, progression-free survival, and MM-free survival rates were 84.2%, 67.3% and 75.9%, respectively. Complete resection without major functional damage is a promising option that can favorably improve prognosis in patients with resectable disease. Patients with regional lymph node metastasis or positive immunoelectrophoresis results require more aggressive treatment and may have poorer prognosis.