Presentation
Severe low back pain. Pre-op assessment for spinal fusion of bilateral L5 pars defects
Patient Data
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CT for low back pain shows chronic bilateral pars defects of L5 with anterior spondylolisthesis and secondary marked spondylarthritis at L5/S1. No abnormality seen in S1.
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MRI performed as part of the pre-op workup by a spinal surgeon shows diffuse infiltration (replacement of normal bone marrow) of sacrum and left ilium with a pathological left ilial fracture presumed to be responsible for severe pain.
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PET shows hyperglucose metabolism in the left hemipelvis and sacrum as well as multiple mediastinal and hilar lymph nodes, and left supraclavicular lymph nodes
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Enlarged dysmorphic left nodes in left supraclavicular fossa biopsied under US control showing metastatic small cell carcinoma
Case Discussion
This study shows how insensitive CT can be for diffuse tumor infiltration of bone and highlights the fact that MRI is the investigation of choice for low back pain. CT should be limited to investigation of acute trauma to the lumbar spine and for confirmation of suspected bone lesions as initially seen on MRI.