A 3-year-old boy presented with progressive lower extremity weakness and difficulty walking for 2 months. Neurologic examination found the muscle strength of his left lower limb was grade 3 and tendon reflex was weakened. MRI demonstrated an intradural extramedullary mass between T10-11 with multiple and diffuse enhancement of thickened nerve roots and spinal dura (Figure). Juvenile xanthogranuloma was suspected as positive staining for CD68 and negative for S100 and CD1a, while immunoreactivity for ALK did not support it. The genetic test confirmed the diagnosis of ALK-positive histiocytosis with KIF5B-ALK fusion, which is a relatively new subtype of histiocytic disease.1,2
(A, B) Postcontrast TIW images revealed an obviously enhanced intradural extramedullary mass between T10-11 (C) with multiple and diffuse enhancement of thickened nerve roots and spinal dura. (D) Nodular-like enhancement lesion centered at the C4 neuroforamen. (E, F) Extensive abnormal enhancement of thoracic and lumbar nerve roots, especially the cauda equina.
Study Funding
No targeted funding reported.
Disclosure
The authors report no disclosures relevant to the manuscript. Go to Neurology.org/N for full disclosures.
Appendix Authors
Footnotes
Go to Neurology.org/N for full disclosures.
Submitted and externally peer reviewed. The handling editor was Roy Strowd III, MD, Med, MS.
Teaching slides links.lww.com/WNL/B911
- Received October 26, 2021.
- Accepted in final form March 2, 2022.
- © 2022 American Academy of Neurology
References
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