Chest X-Ray Findings in Multiple Myeloma with Diplopia
In a patient with multiple myeloma presenting with diplopia, the chest x-ray most commonly shows lytic bone lesions of the ribs, sternum, or vertebrae, and may reveal pleural effusion (occurring in approximately 6% of MM cases), though the chest x-ray is often normal as pulmonary parenchymal involvement is rare. 1
Primary Skeletal Findings
Lytic bone lesions are the hallmark chest x-ray finding in multiple myeloma:
- Rib destruction and lytic lesions are the most frequent thoracic manifestation, appearing as punched-out radiolucent areas in the ribs, sternum, clavicles, and thoracic vertebrae 1, 2
- Advanced bone lesions correlate with Stage III disease in the Durie-Salmon classification and indicate more aggressive disease 1
- Pathological fractures of ribs or vertebrae may be visible, particularly in patients with severe osteopenia 1, 3
- Chest wall soft tissue masses can develop from rib plasmacytomas extending into adjacent soft tissues 2
Pleural Involvement
Pleural effusion is an uncommon but important finding:
- Pleural effusion occurs in approximately 6% of MM cases and typically develops from chest wall invasion by adjacent skeletal lesions (ribs, sternum, vertebrae) 1
- The effusion is usually an exudate with characteristically high protein values (8-9 g/L), which should prompt consideration of MM in the differential diagnosis 1
- Effusions may be unilateral or bilateral and can be serous or hemorrhagic 1
Pulmonary Parenchymal Findings (Rare)
Direct pulmonary involvement is uncommon but carries poor prognosis when present:
- Diffuse bilateral alveolar-interstitial infiltrates may appear in rare cases of direct plasma cell infiltration of lung parenchyma 4, 5
- Interstitial infiltration with ground-glass opacities can occur, though this is an unusual presentation requiring tissue confirmation 6, 5
- Mass lesions or multiple nodular opacities represent extramedullary plasmacytomas, which are exceedingly rare 4
- Pulmonary parenchymal involvement is associated with rapid disease progression, renal failure, and poor prognosis 4
Clinical Context: Diplopia Connection
The diplopia in this patient likely indicates skull base or orbital bone involvement:
- While diplopia suggests cranial nerve involvement from skull base plasmacytomas or lytic lesions, the chest x-ray findings reflect systemic skeletal disease burden 1
- Full skeletal survey including chest is mandatory for staging, as recommended by ESMO guidelines 1
- The presence of chest wall bone lesions on x-ray would support Stage III disease if extensive 1
Important Diagnostic Caveats
Chest x-ray has significant limitations in MM evaluation:
- Normal chest x-ray does not exclude significant disease - MRI or PET-CT are more sensitive for detecting early bone marrow involvement and should be performed if skeletal survey is negative 1
- Infectious complications are more common than direct pulmonary MM involvement - pneumonia is the most frequent cause of pulmonary infiltrates in MM patients, not malignant infiltration 4, 7
- Drug-induced pulmonary toxicity (such as thalidomide-induced BOOP) can mimic MM pulmonary involvement and must be excluded 6
Recommended Imaging Approach
Beyond chest x-ray, advanced imaging is essential:
- Whole-body low-dose CT (WBLD-CT) is now the obligatory imaging modality at diagnosis per 2021 EHA-ESMO guidelines, as it is more sensitive than plain radiographs 1
- PET-CT should be performed if WBLD-CT is negative or to assess for extramedullary disease 1
- MRI of spine is recommended if spinal cord compression is suspected, which could explain neurological symptoms like diplopia if cervical spine is involved 1