A common case with an unusual association: Chiari I malformation with holocord syrinx.

Authors are presenting a common case of Chiari malformation but with a very unusual associated finding, holocord syringomyelia, which responded to posterior fossa decompression. An 11-year-old male patient presented with progressive left hemiparesis and numbness on left half of the body for 4 years. Magnetic resonance imaging of the spine revealed peg-shaped herniation of tonsils 8 mm below the foramen magnum and holocord syringomyelia. No focal intraspinal mass was seen. Chiari I malformation with holocord syrinx was diagnosed. The patient underwent posterior fossa decompression with subpial resection of both tonsils with augmentation duraplasty. Post-operatively, patient improved clinically as well as radiologically.