Objective: Extramedullary plasmacytoma (EMP) defines soft tissue tumors that are characterized by plasma cell infiltration and develop secondary to hematogenous spread, in an anatomical site distant from the bone marrow (usually liver, skin, central nervous system, pleura, kidneys, lymph nodes, and pancreas) (3,4). The prevalence of EMP in MM patients is approximately 6–8% at diagnosis and approaches 10–30% during the course of the disease. Here, we present a case of relapsed MM concomitant with a large EMP surrounding the aorta, which is an extremely rare pattern of involvement.
Case report: A 66-year-old male patient presented to our clinic with back pain and weakness in the legs. The patient had been diagnosed with IgG kappa multiple myeloma six years ago. In the initial diagnosis, he had been evaluated as an ISS stage-II, transplant eligible based on clinical and laboratory findings. He had received monthly zoledronic acid, two courses of VAD and two courses of VD regimens. Subsequent to complete response, he had undergone aHSCT with high-dose melphalan for the purpose of consolidation. The patient had achieved complete remission under follow-up after aHSCT. The disease had relapsed approximately 4 years after the first aHSCT, and the patient had undergone another aHSCT with high-dose chemotherapy after a VCD chemotherapy regimen, and had been in complete remission under follow-up. He presented with the complaints stated above 18 months after the second transplantation. On physical examination, bilateral lower extremities showed weakness and impaired sensation. Spinal vertebrae were examined with MRI in consideration of the history of MM. On MRI examination, there were diffuse lytic lesions involving all spinal segments and the sternum, and a soft tissue lesion that involved the aorta-vascular structures in the retrocrural space at the level of T7-L1 and extended to the spinal canal and involved the spinal cord at the level of T8-10. An imaging-guided tru-cut biopsy was taken from the mass and the diagnosis was confirmed as plasma cell myeloma based on histopathological and immunohistochemical findings. Although the patient underwent 2 courses of Len-Dex, and subsequently, 2 courses of VRD, there was no reduction in the size of the plasmacytoma, and the patient was considered non-responsive. As a more aggressive regimen, a combination of VDT-PACE was administered. A very good partial response was obtained after two courses. The patient was not suitable for allogeneic HSCT because of poor performance status. The patient and his relatives were consulted, and it was decided to continue the treatment with chemotherapy agents.
Conclusion: In conclusion, EMPs, although infrequently, are encountered during the course of multiple myeloma and its relapse. EMPs can be found in very rare localizations. Symptoms vary depending on the anatomical localization of the masses or the dysfunctions that result from the direct mass effect or organ involvement. In this regard, radiological, laboratory, and histopathological evaluation of massive lesions during follow-up is important. Particularly, MRI can be effective as an imaging method in the diagnosis and close follow-up of patients with symptoms associated with extramedullary plasmacytomas.
