Hot cross bun sign (pons)

Last revised by Magdi Mahsoub on 21 Jan 2025

Citation, DOI, disclosures and article data

Citation:

Gaillard F, Mahsoub M, Sharma R, et al. Hot cross bun sign (pons). Reference article, Radiopaedia.org (Accessed on 09 Mar 2025) https://doi.org/10.53347/rID-13008

DOI:

https://doi.org/10.53347/rID-13008

Permalink:

https://radiopaedia.org/articles/13008

rID:

13008

Article created:

16 Feb 2011, Frank Gaillard ◉ ◈

Disclosures:

At the time the article was created Frank Gaillard had no recorded disclosures.

View Frank Gaillard's current disclosures

Last revised:

21 Jan 2025, Magdi Mahsoub

Disclosures:

At the time the article was last revised Magdi Mahsoub had no financial relationships to ineligible companies to disclose.

View Magdi Mahsoub's current disclosures

Revisions:

21 times, by 12 contributors - see full revision history and disclosures

Systems:

Central Nervous System

Sections:

Signs

Synonyms:

Reverse hot cross bun sign (pons)
Hot cross bun sign (medulla)
Hot cross bun sign
Reverse hot cross bun sign

The hot cross bun sign refers to the MRI appearance of the pons when T2 hyperintensity forms a cross on axial images, representing selective degeneration of transverse pontocerebellar tracts and median pontine raphe nuclei ¹.

It has been described in a variety of neurodegenerative and other conditions. Common associations include:

multiple system atrophy (MSA), a classic sign but not pathognomonic ¹
spinocerebellar ataxia (various types) ⁵

Other causes, which are either very rare or in which presence of the hot cross bun sign is rarely reported, include ¹⁷:

autoimmune/paraneoplastic rhombencephalitis (e.g. anti-KLHL11, anti-Ri, anti-amphiphysin, anti-Homer-3) ^{7,10,14,15,16}
bilateral cerebellar ischemic stroke of the middle cerebellar peduncles ⁶
cerebral vasculitis (causing Wallerian degeneration of pontocerebellar tracts) ⁴
cerebrotendinous xanthomatosis ¹²
corticobasal degeneration ⁹
JC virus granule cell neuronopathy ³
neurosarcoidosis ¹³
oculodentodigital dysplasia ¹¹
paraneoplastic cerebellar degeneration ⁸
variant Creutzfeldt-Jakob disease (vCJD) ²

Differential diagnosis

a similar hot cross bun sign appearance may be seen in the medulla (rather than pons) in adult-onset Alexander disease ^17,18
a 'reverse' hot cross bun sign in the pons, whereby T2 hypointensity forms a cross on axial images, has rarely been described in pathologies such as pontine infarction, Wilson disease, and primary progressive aphasia ^19-21

References

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2. Soares-fernandes JP, Ribeiro M, Machado A. "Hot cross bun" sign in variant Creutzfeldt-Jakob disease. AJNR Am J Neuroradiol. 2009;30 (3): E37. doi:10.3174/ajnr.A1335 - Pubmed citation
3. Henry C, Jouan F, De Broucker T. JC virus granule cell neuronopathy: A cause of infectious cerebellar degeneration. (2015) Journal of the neurological sciences. 354 (1-2): 86-90. doi:10.1016/j.jns.2015.05.003 - Pubmed
4. Muqit MM, Mort D, Miskiel KA, Shakir RA. "Hot cross bun" sign in a patient with parkinsonism secondary to presumed vasculitis. (2001) Journal of neurology, neurosurgery, and psychiatry. 71 (4): 565-6. Pubmed
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6. Nishida K & Futamura N. Hot Cross Bun Sign in Bilateral Middle Cerebellar Peduncle Infarction. Stroke. 2023. doi:10.1161/strokeaha.122.042453 - Pubmed
7. Majed M, Madhavan A, Pittock S, Dubey D. “Hot Cross Bun” Sign in a Patient With Kelch-Like Protein 11 Rhombencephalitis. Mayo Clin Proc. 2022;97(1):122-3. doi:10.1016/j.mayocp.2021.11.024 - Pubmed
8. Ishikawa H, Kawada N, Taniguchi A et al. Paraneoplastic Neurological Syndrome Due to Burned-Out Testicular Tumor Showing Hot Cross-Bun Sign. Acta Neurol Scand. 2015;133(5):398-402. doi:10.1111/ane.12469 - Pubmed
9. Ando T, Yokoi F, Riku Y et al. The Hot Cross Bun Sign in Corticobasal Degeneration. Neuropathology. 2021;41(5):376-80. doi:10.1111/neup.12745 - Pubmed
10. Liu Y, Huang D, Wu L. Occult Breast Cancer With Anti-Ri Antibody Positivity and Pontine Hot Cross Bun Sign. JAMA Neurol. 2023;80(2):207. doi:10.1001/jamaneurol.2022.4663 - Pubmed
11. Constantinides V, Paraskevas G, Kalogera S, Yapijakis C, Kapaki E. Hot Cross Bun Sign and Prominent Cerebellar Peduncle Involvement in a Patient with Oculodentodigital Dysplasia. Neurol Sci. 2020;42(1):343-5. doi:10.1007/s10072-020-04569-1 - Pubmed
12. Jain R, Sannegowda R, Agrawal A, Hemrajani D, Jain R, Mathur T. 'Hot Cross Bun' Sign in a Case of Cerebrotendinous Xanthomatosis: A Rare Neuroimaging Observation. Case Reports. 2013;2013(feb14 1):bcr2012006641. doi:10.1136/bcr-2012-006641 - Pubmed
13. Nagpal K & Agarwal P. "Hot-Cross Bun" and "Inverse Trident Sign' in Neurosarcoidosis: An Important Finding. Neurol India. 2017;65(1):175-6. doi:10.4103/0028-3886.198227 - Pubmed
14. Schlapakow E, Keil V, Paus M, Kornblum C, Hattingen E, Klockgether T. Multiple System Atrophy Mimicry in MRI: Watch out for Paraneoplastic Rhombencephalitis. J Clin Neurosci. 2020;76:238-40. doi:10.1016/j.jocn.2020.04.052 - Pubmed
15. Liu M, Ren H, Fan S et al. Neurological Autoimmunity Associated With Homer-3 Antibody. Neurol Neuroimmunol Neuroinflamm. 2021;8(6):e1077. doi:10.1212/nxi.0000000000001077 - Pubmed
16. Liu M, Ren H, Lin N, Tan Y, Fan S, Guan H. The “hot Cross Bun Sign” in Patients with Autoimmune Cerebellar Ataxia: A Case Report and Literature Review. Front Neurol. 2022;13:979203. doi:10.3389/fneur.2022.979203 - Pubmed
17. Fang X & Liang H. Medullary Hot-Cross Bun Sign in Adult-Onset Alexander Disease. Neurol India. 2024;72(1):234. doi:10.4103/neurol-india.neurol-india-d-23-00676 - Pubmed
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21. Jain R, Kumar K, Ashwini H. Reverse ’Hot Cross Bun’ Sign in Primary Progressive Aphasia - An Atypical MRI Feature. ANAMS. 2020;54(3):171-4. doi:10.1055/s-0040-1712843