We report on a case of a 47-year-old female patient with a long history of low back pain irradiating bilaterally to the legs. Twenty days before admission to our clinic, she had developed progressive weakness in the legs, more pronounced on the left side. The initial neurological examination revealed signs of damage to both the cauda equina and the spinal cord. The neuroimaging studies (computed tomography, myelography and magnetic-resonance tomography) found spinal stenosis most severe at L4-L5 level, and right lateral thoracic intradural-extramedullary tumor at T9-T10 level. The patient underwent two neurosurgical procedures. The first stage included microsurgical resection of the thoracic lesion and the second stage aimed at decompressing the lumbar spinal stenosis. To avoid missing a diagnosis of thoracic lesions, it is necessary to perform a thorough neurological examination of the spinal cord motor and sensory functions. In addition, further MRI examination of upper spinal segment is needed if the neuroimaging studies of the lumbar spine fail to provide reasonable explanation for the existing neurological symptoms.