Objectives This report is of a case of Froin’s syndrome seen at a tertiary neurology centre caused by severe lumbar disc protrusion, a finding that has been only rarely reported in historical literature.

Case A 40 years old man with previously treated latent tuberculosis presented with two weeks of progressive right leg weakness. Nerve conduction studies suggested evidence of right lumbosacral plexopathy. On lumbar puncture, CSF was yellow coloured, thick in consistency and CSF flow spontaneously stopped after draining 8 mls. CSF chemistry revealed protein of 30 000 mg/L, glucose of 0.2 mmol/L and no white cells. CSF microscopy and cultures for acid fast bacilli were negative. MRI of lumbosacral spine revealed severe L5 disc protrusion with cauda equina and a cul-de-sac of CSF with increased signal on T2 weighted images distal to disc protrusion.

Conclusions This case revisits a clinical finding described in early 1900s before the advent of modern imaging, and illustrates the importance of knowledge of historical clinical literature in interpreting an uncommon finding of CSF xanthochromia. To the best of our knowledge, raised CSF protein due to a non-infective, non-malignant and non-inflammatory cause as in our case, has been the highest ever reported in published literature.