Plasmablastic myeloma with a history of diffuse large B-cell lymphoma

Plasmablastic myeloma is a rare subtype of multiple myeloma, accounting for 5-10% of all cases, associated with poorer survival rates than typical multiple myeloma. This case report presents a man with plasmablastic myeloma with a previous history of diffuse large B-cell lymphoma which was in remission. He presented with paraplegia due to spinal cord compression and severe weakness. Investigations revealed abnormal immunoglobulin levels, hypercalcaemia and 80-90% bone marrow infiltration by plasmablasts. MRI revealed multiple spinal metastases and an incidental 6.1 cm abdominal aortic aneurysm. Treatment given involved radiotherapy, three rounds of chemotherapy and physiotherapy. The patient showed improvement after radiotherapy, though some spinal lesions still remained. Key challenges included differentiating plasmablastic myeloma from plasmablastic lymphoma due to the history of diffuse large B-cell lymphoma as well as balancing treatment risks from concurrent health issues.