The epidural space is the most common site of metastases producing injury to the spinal cord. The incidence is 5% to 10% and up to 40% in patients with pre-existing nonspinal bone metastases.
Tumors of the sacrum are rare. Metastases are the most common malignant tumors of the sacrum, derived from lung, breast, kidney, prostate, head and neck, gastrointestinal or skin (melanoma) cancers; these will not be discussed further.