Lumbar-disc protrusions (LDP) constitute well-defined syndromes on clinical and anatomical grounds, and neurosurgeons are prone to rely upon the clinical signs to identify the level of disc protrusion when a «typical» case is found. Sometimes, non-contrasted computerized tomographic (CT) scans centered on the L5-S1, L4-L5 and L3-L4 interspaces and spine roentgenograms are the only special ancilary means in presurgical evaluation. We report three patients from our series, in which neoplasic spinal disease presented as classic LDP (one patient with a cauda equina schwannoma, and two with metastatic carcinoma). The cases were chosen because they posed special problems to the referred radiodiagnostic routine. Systematic CT-evaluation of the sacrum and conus medullaris zone is recommended in every patient with lumbosacral radiculopathy, and intratecal contrast should be employed in patients with unreliable findings or normal CT-scans.