What further workup is needed for an elderly female patient with myelodysplastic syndrome (MDS) and incidental findings of multiple vertebral lesions at T1, T3, T6, and L1 on MRI, after a fall, with no neurological symptoms?

Further Workup for Vertebral Lesions in MDS Patient

This patient requires immediate evaluation to rule out plasma cell dyscrasia (multiple myeloma or plasmacytoma), which is the most critical differential diagnosis for multiple vertebral lesions in a patient with an underlying hematologic disorder like MDS. 1

Priority Diagnostic Workup

Serum and Urine Studies (First-Line)

• Serum protein electrophoresis (SPEP) with immunofixation to detect monoclonal protein 1
• Serum free light chain assay (kappa/lambda ratio) for light chain disease 1
• 24-hour urine protein electrophoresis with immunofixation to detect Bence Jones protein 1
• Quantitative immunoglobulins (IgG, IgA, IgM) 1
• Serum calcium, creatinine, and albumin to assess for hypercalcemia and renal dysfunction (CRAB criteria) 1
• Complete blood count with differential and LDH for prognostic assessment 2

Bone Marrow Evaluation (Essential)

• Bone marrow aspiration and biopsy with specific attention to plasma cell percentage 1
• Flow cytometry or immunohistochemistry to quantify clonal plasma cells (using kappa/lambda staining), as the malignant phenotype in plasma cell disorders can be detected with high sensitivity 1
• Cytogenetic analysis should be repeated as MDS patients can develop secondary malignancies, and clonal evolution must be assessed 1

Critical threshold: Bone marrow plasma cells >10% would definitively diagnose multiple myeloma rather than solitary plasmacytoma 1

Advanced Imaging Considerations

• Whole-body low-dose CT or PET/CT is recommended to fully characterize the extent of skeletal involvement and exclude additional occult lesions 1
• The current MRI findings of multiple lesions at T1, T3, T6, and L1 already suggest systemic disease rather than solitary plasmacytoma 1
• Contrast-enhanced MRI of the spine may help assess for soft tissue extension or impending spinal cord compression, even in the absence of current neurological symptoms 1

Key Diagnostic Distinctions

Why Plasma Cell Dyscrasia is the Primary Concern

Multiple vertebral lesions in an elderly patient with MDS raise immediate concern for:

• Multiple myeloma (if bone marrow plasma cells >10% with end-organ damage) 1
• Multiple solitary plasmacytomas (if bone marrow plasma cells <10% but multiple skeletal lesions present) 1

The pattern of multiple discrete vertebral lesions with T1 hypointensity on MRI is characteristic of plasma cell infiltration 1

MDS-Related Bone Lesions Are Uncommon

• MDS itself does not typically cause focal lytic bone lesions 1
• MDS primarily manifests with bone marrow dysplasia and cytopenias, not discrete skeletal lesions 1, 2
• The vertebral lesions are therefore likely representing a separate pathologic process requiring distinct evaluation 1

Critical Pitfalls to Avoid

• Do not assume these lesions are related to MDS without excluding plasma cell dyscrasia, as this would delay appropriate treatment 1
• Do not wait for neurological symptoms to develop before completing the workup, as spinal cord compression can occur suddenly and represents an oncologic emergency 1
• Do not skip bone marrow evaluation even if serum/urine studies are positive, as the plasma cell percentage determines whether this is myeloma versus plasmacytoma and guides treatment 1
• Do not order only regional imaging—whole-body assessment is essential to distinguish solitary from multiple lesions and to properly stage disease 1

Relationship to Underlying MDS

• Patients with MDS have increased risk of secondary malignancies due to clonal hematopoiesis and immune dysregulation 2
• The presence of both MDS and plasma cell dyscrasia would significantly impact prognosis and treatment planning 1, 2
• If multiple myeloma is confirmed, treatment decisions must account for existing cytopenias from MDS, as many myeloma therapies cause additional myelosuppression 1