Dilated Internal Thoracic Vertebral Venous Plexus Simulating Bone Metastases on FDG PET/CT

Area of Science:

• Oncology
• Radiology
• Medical Imaging

Background:

• Malignant thymoma diagnosis and staging.
• FDG PET/CT and contrast-enhanced CT interpretation.
• Superior vena cava syndrome and its complications.

Observation:

• A 42-year-old woman with newly diagnosed malignant thymoma presented with increased FDG PET/CT uptake in the anterior mediastinum and pleural masses.
• CT revealed a hyperdense abnormality in the T2 vertebral body, suspicious for skeletal metastasis.
• FDG PET/CT showed intense uptake in the vertebral lesion, further suggesting metastasis.

Findings:

• The vertebral lesion was ultimately identified as a false-positive finding.
• The abnormality was attributed to a dilated internal thoracic vertebral venous plexus.
• This venous plexus was associated with collateral circulation secondary to superior vena cava syndrome.

Implications:

• Highlights a rare but significant imaging pitfall in evaluating malignant thymoma.
• Emphasizes the importance of considering venous anomalies in the differential diagnosis of bony lesions.
• Underscores the need for careful correlation of imaging findings with clinical context to avoid misdiagnosis of skeletal metastasis.