Indian Society of Paediatric Radiology

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Quiz Answer February 2024

Opsoclonus myoclonus ataxia syndrome (OMAS)

qaFeb2401.jpg ISPR Quiz Feb 2024

Normal MRI brain study. (A) Axial T2-FLAIR, (B) Axial, (C) Sagittal T1W, (D) Axial SWI MIP images



qaFeb2402A.jpg ISPR Quiz Feb 2024

(A) Axial , (C) coronal , (D) Sagittal T2W, (B) T1 post-contrast images showing a well-defined enhancing right suprarenal mass showing near homogenous T2 hyperintensity and no neural canal invasion (red arrows). Tumor was excised in-toto. Child is currently receiving immunomodulation therapy.



Discussion

Paraneoplastic syndrome secondary to neurogenic tumor. MRI brain was normal, but right suprarenal mass was found on spine screening and further characterized with MRI. Mass was FDG PET avid, but MIBG negative. Mass excised and histopathology revealed ganglioneuroblastoma.

qaFeb2403.jpg ISPR Quiz Feb 2024

(A) Axial CT, (B) fused 18F-FDG PET/CT image showing FDG avid right adrenal mass (red arrow).

  • Opsoclonus-myoclonus-ataxia syndrome (OMAS) is a rare disorder of the nervous system with onset usually in the second year of life.
  • Classically presents with a combination of characteristic eye movement disorder and myoclonus, in addition to ataxia, irritability, and sleep disturbance.
  • In around 50% of children presenting with OMAS, there is an underlying neuroblastoma. There is good evidence that OMAS is an immune-mediated condition that may be paraneoplastic in the context of neuroblastoma.
  • 18F-FDG PET/CT may be useful in patients with neurogenic tumors which are either weakly positive or negative on 123I-MIBG.

References

  • Gorman MP. Update on diagnosis, treatment, and prognosis in opsoclonus-myoclonus-ataxia syndrome. Curr Opin Pediatr 2010;22(6):745-750.
  • Rossor T, Yeh EA, Khakoo Y, Angelini P, Hemingway C, Irani SR et al. Diagnosis and Management of Opsoclonus-Myoclonus-Ataxia Syndrome in Children: An International Perspective. Neurol Neuroimmunol Neuroinflamm. 2022 Mar 8;9(3):e1153.
  • Sharp SE, Shulkin BL, Gelfand MJ, Salisbury S, Furman WL. 123I-MIBG scintigraphy and 18F-FDG PET in neuroblastoma. J Nucl Med. 2009 Aug;50(8):1237-43.