Teaching Case

Destructive vertebral lesion with cord compression.

A 74 year old female presented with severe thoracic back pain . There was no history of trauma. Neurological examination was normal. Radiographs of the thoracic spine (fig.1) showed destruction of the left pedicle of T 11 and partial destruction of the inferior end plate of T10 . MRI of the lumbar spine (fig.2a) demonstrated complete destruction of the T11 vertebral body, left pedicle and lamina. There was also a significant epidural soft tissue component displacing and compressing the cord at this level (Fig 2b,c). An isotope (Technetium 99) bone scan (fig.3) demonstrated focal increased uptake in the spine corresponding to the described levels and also in the right scapula. Radiographs of the right shoulder (not shown) confirmed a large,purely lytic lesion in the glenoid . A photopaenic area was present in the lower pole of the right kidney associated with fullness of the pelvicalyceal system,suspicious of a space occupying lesion . Renal ultrasound (fig.4)demonstrated a 5 cm solid lesion in the lower pole of the right kidney. CT scan of the right kidney (not shown) confirmed a solid, soft tissue density tumour with inhomogeneous enhancement. Percutaneous biopsy of the T11 vertebra under CT guidance (fig.5) demonstrated a clear cell carcinoma consistent with a metastasis from renal cell cancer. Arteriography showed a highly vascular lesion involving the body of T11 supplied by the left 11th intercostal artery (fig.6a). Embolisation was performed using polyvinyl alcohol particles 250 – 355 microns in diameter via a 4 Fr catheter. Post - embolisation arteriography showed devascularisation of the tumour (fig 6b). There were no complications. The patient subsequently underwent an uneventful vertebrectomy and stabilisation of the spine (fig. 7).

Metastatic spine disease is frequent in renal cell carcinoma and 50% of osseous metastases are already found at the time of primary diagnosis. [1] The vertebral bodies are affected due to the highly vascularised marrow space . Most spinal metastases (approximately 68%) involve the thoracic spine. [2] Although most metatases will be shown on bone scintigraphy, MRI is the most sensitive technique for detecting spinal metastases and for assessing local complications such as cord compression. T1-weighted sagittal images of the entire cervical and thoracic spine may be obtained with a phased-array coil and have proved to be a very sensitive and rapid method for surveying for vertebral metastases. [3] Metastatic renal cell carcinoma is usually purely lytic having the same T1 and T2 relaxation times as the primary tumour ( low signal on T1W- and high signal on T2W- images ) and shows enhancement after Gd-DTPA adminstration. [4] Renal cell carcinoma metastases are in general hypervascular. Care has to be taken during biopsy and the use of fine needles or trucut needles is preferred to reduce the risk of post-procedure haemorrhage. Embolisation of vertebral metastases is recommended prior to surgical resection. The resulting devascularisation allows for an aggressive resection of pathologic tissue [5].Normally bilateral embolisation of intercostal arteries at the affected level is performed,however,in the above case satisfactory devascularisation was obtained following embolisation of the left side only .Furthermore, the right intercostal artery was difficult to catheterise due to an atheromatous,ectatic aorta.It is essential to obtain a stable catheter position in the supplying artery prior to beginning an embolisation procedure.If this can be achieved with a 4 or 5 Fr catheter then this is satisfactory since the insertion of additional co-axial catheters may increase the risk of complications by prolonging the procedure.