- Spinal Disorders Center, Fujieda Heisei Memorial Hospital, Fujieda, Japan.
Ryo Kanematsu, Spinal Disorders Center, Fujieda Heisei Memorial Hospital, Fujieda, Japan.
DOI:10.25259/SNI_756_2022Copyright: © 2022 Surgical Neurology International This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-Share Alike 4.0 License, which allows others to remix, transform, and build upon the work non-commercially, as long as the author is credited and the new creations are licensed under the identical terms.
How to cite this article: Ryo Kanematsu, Junya Hanakita, Toshiyuki Takahashi, Manabu Minami, Izumi Suda, Sho Nakamura, Shu Takeuchi, Yoshitaka Tsujimoto. Retro-odontoid pseudotumor presenting double layer on MRI: A case report. 30-Sep-2022;13:446
How to cite this URL: Ryo Kanematsu, Junya Hanakita, Toshiyuki Takahashi, Manabu Minami, Izumi Suda, Sho Nakamura, Shu Takeuchi, Yoshitaka Tsujimoto. Retro-odontoid pseudotumor presenting double layer on MRI: A case report. 30-Sep-2022;13:446. Available from: https://surgicalneurologyint.com/surgicalint-articles/11904/
Background: Retro-odontoid pseudotumors (ROPs) typically present as a single mass posterior to the odontoid ranging from isointense to hypointense relative on T1-weighted magnetic resonance (MR) imaging (MRI T1WI). Here, a patient with ROP exhibited the double-layer sign on the MRI T1WI characterized by an initial ventral layer posterior to the odontoid process followed by a secondary dorsal layer.
Case Description: An 84-year-old male presented with cervical myelopathy attributed to ROP resulting in atlantoaxial instability on dynamic X-ray studies, and the double-layer sign on the T1 MR accompanied by a cystic component. MR following C1–C2 posterior fusion, the patient’s myelopathy resolved and both layers spontaneously regressed on the follow-up MR studies.
Conclusion: The MR-documented double layer sign with ROP, likely attributable to reactive hypertrophy of the transverse ligament with cystic components, may demonstrate spontaneous MR regression with symptom resolution following a C1–C2 posterior fusion.
Keywords: Double layer, Pseudotumor, Retro-odontoid tumor
Double-layer retro-odontoid pseudotumors (ROPs) are nonneoplastic inflammatory lesions (i.e., most likely due to mechanical stress and composed of fibrous granulation/fibrocartilaginous tissues) that may extend from the clivus to the C2–C4 levels and contribute to spinal compression.[
An 84-year-old male presented with cervical myelopathy due to ROP. Flexion-extension roentgenograms showed atlantoaxial subluxation. T1 and T2 MR studies demonstrated ROP and the double-layer sign; T1 unenhanced MR studies showed that both layers were isointense areas while T2 MR showed a mixed intensity secondary dorsal layer [
Preoperative magnetic resonance imaging (MRI) T1WI and T2WI sagittal view. T1-weighted magnetic resonance (MR) imaging demonstrated retro-odontoid pseudotumor with double-layer sign; T1 MR showed both layers with isointense areas (a) while T2 MR showed mixed intensity areas of a secondary dorsal layer (b).
Etiology of ROP double-layer sign
Some causes of ROP involve cyst formation, which can potentially grow to exceptionally large sizes extending from clivus to the caudad C2–C4 levels [
The MR-documented double-layer sign with ROP was likely attributable to reactive hypertrophy of the transverse ligament with cystic components. Spontaneous regression of the double-layer sign after posterior C1–C2 fusion correlated with the patient’s resolved myelopathy.
The authors certify that they have obtained all appropriate patient consent.
There are no conflicts of interest.
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