Herniated intervertebral disc mimicking intraspinal tumor

Lumbar disc herniation is a relatively common disease. Magnetic resonance imaging (MRI) is the first-used diagnostic tool for evaluating spinal pathologies and represents adiagnostic gold standard. However, the diagnosis of intervertebral disc herniation can still be very difficult in some cases, even in this MRI era. Considering that little is known about this area, and to share our experience, we present here a special case of a herniated intervertebral disc mimicking an intraspinal tumor. A 43-year-old female patient presented to our hospital with a history of low back pain and right limb numbness and pain for 60 days. Physical examination showed tenderness and percussion pain in her lower back, and decreased myodynamia of her right limb (Grade 2). Hypoaesthesia was detected below the distribution of L4 while the sensation in the saddle area was not damaged. MRI provided evidence for a herniated intervertebral disc at L5/S1 but also revealed a strong signal in the spinal canal at the level of the L5 vertebra. The diagnosis: "intraspinal occupying lesion: neurofibroma?" was made before performing surgery. To our surprise, a lump of white tissue similar to nucleus pulposus was found in the spinal canal during surgery. Postoperative pathological hematoxylin and eosin staining confirmed its character to be that of nucleus pulposus. Herniated intervertebral discs generally produce signals of low intensity in T1-weighted images but high intensity in T2-weighted images. Gadolinium-enhanced MRI can be used to differentiate a tumor from a herniated intervertebral disc. Differential diagnosis is important when making surgical plans but the final, definitive, diagnosis depends on pathological examination.