대한흉부영상의학회 Korean Society of Thoracic Radiology

Discussion

Diagnosis With Brief Discussion

Diagnosis

multiple myeloma with thoracic paraskeletal involvement

Radiologic Findings

He was diagnosed with multiple myeloma with thoracic paraskeletal involvement through VATS biopsy and bone marrow biopsy.

Figure 1. Chest radiography reveals bilateral pleural effusions, with more on the left side. Additionally, there were somewhat increased bronchovascular bundle markings and ill-defined patchy opacities in both hemithoraces.

Figure 2. Axial view contrast-enhanced chest CT scan reveals multifocal pleural nodular lesions and pleural effusion in both hemithoraces.

Figure 3. On the oblique axial reconstruction image, the lesions appear as a continuous band-like soft tissue density with a smooth margin along each rib.

Figure 4. 5 On the coronal and sagittal images, the lesions are surrounding the inner surface of each rib.

Brief Review

Multiple myeloma (MM) is the most frequent cancer to involve the skeleton, with 80–90% of patients developing bone lesions. Myeloma bone lesions are purely osteolytic and are associated with bone pain, pathologic fractures, hypercalcemia, spinal cord compression, and increased mortality. Some patients develop soft-tissue involvement, with clonal plasma cells found outside the bone marrow.
A previous expert consensus review has endorsed the definition and distinction of soft-tissue involvement in MM: a) paraskeletal involvement with tumor masses arising from skeletal lesions and b) extramedullary involvement with hematogenous spread involving only soft tissue. The mechanism resulting in soft tissue plasmacytomas is direct growth from skeletal tumors by disrupting the cortical bone, while the remaining tumors result from hematogenous spread without contact with bony structures.
In this case, chest CT did not reveal adjacent cortical destruction or definite osteolytic lesions, leading to the initial diagnosis of an extrapleural space tumor of the thorax. Subsequent MRI and PET-CT scans (not shown here) confirmed systemic diffuse bone marrow lesions and a diagnosis of MM with thoracic paraskeletal involvement was established through VATS and bone marrow biopsy.

References

1. Blade J, Fernandez de Larrea C, Rosinol L, Cibeira MT, Jimenez R, Powles R. Soft-tissue plasmacytomas in multiple myeloma: incidence, mechanisms of extramedullary spread, and treatment approach. J Clin Oncol 2011;29:3805-12.
2. Blade J, Beksac M, Caers J, et al. Extramedullary disease in multiple myeloma: a systematic literature review. Blood Cancer J 2022;12:45.

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