Rare Locations of Plasma Cell Tumour: A Single-Centre Experience

Extramedullary involvement, also known as Extramedullary Disease (EMD), represents a highly aggressive variant of plasma cell dyscrasias. It is characterised by the presence of plasma cell clones that proliferate independently of the bone marrow microenvironment. While EMD most commonly affects the skin and soft tissues, in cases of disease relapse, it may extend to internal organs, including the liver, kidneys, central nervous system, chest wall, pleura, and pericardium. The reported incidence of EMD varies. A comprehensive review of the literature indicates that in newly diagnosed Multiple Myeloma (MM) patients, the incidence ranges from 0.5% to 4.5%. However, in relapsed or refractory MM, the incidence increases markedly, reaching between 3.4% and 14%. Prognosis remains poor, particularly when the paravertebral region is involved, as this often leads to vertebral body fractures that complicate treatment and worsen outcomes. Current data on therapeutic responses are primarily based on retrospective studies. Therefore, prospective trials are needed to more accurately assess the efficacy of various treatment regimens. This study presents a cohort of patients with paravertebral plasma cell tumours, with a specific focus on tumour location, associated vertebral fractures, available treatment strategies, and clinical responses following induction therapy.