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Lindsey Bulleid1, Tom Hughes2, Paul Leach1
  1. Department of Neurosurgery, University Hospital of Wales, Cardiff, South Wales, United Kingdom.
  2. Department of Neurology, University Hospital of Wales, Cardiff, South Wales, United Kingdom.

Correspondence Address:
Lindsey Bulleid
Department of Neurosurgery, University Hospital of Wales, Cardiff, South Wales, United Kingdom.

DOI:10.25259/SNI_625_2020

Copyright: © 2021 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, tweak, 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: Lindsey Bulleid1, Tom Hughes2, Paul Leach1. Mollaret’s triangle: An important neuroanatomical territory for all clinicians. 08-Mar-2021;12:94

How to cite this URL: Lindsey Bulleid1, Tom Hughes2, Paul Leach1. Mollaret’s triangle: An important neuroanatomical territory for all clinicians. 08-Mar-2021;12:94. Available from: https://surgicalneurologyint.com/surgicalint-articles/10629/

Date of Submission
09-Sep-2020

Date of Acceptance
22-Jan-2021

Date of Web Publication
08-Mar-2021

Abstract

Background: Hypertrophic olivary degeneration is a rare condition caused by damage within the triangle of Guillain and Mollaret. We discuss the anatomical, radiological, and clinical history of this rare condition.

Case Description: A 32-year-old lady presented with sub-acute headache, photophobia, and dizziness. She also described facial tingling and itching over her nose, and a thirty-minute episode of slurred speech. Magnetic resonance imaging revealed a 12.1 × 11 × 7.3 mm lesion arising from the floor of the fourth ventricle [Figure 1]. Postoperative imaging confirmed complete resection of the tumor, but changes consistent with hypertrophic olivary degeneration [Figure 2a and b].

Conclusion: An awareness of this complication is of importance to all clinical neuroscience to prevent misdiagnosis with the occurrence of new symptoms.

Keywords: Cervical myoclonus, Fourth ventricular tumor, Hypertrophic olivary degeneration, Oscillopsia, Palatal myoclonus, Triangle of Guillain and Mollaret

INTRODUCTION

Hypertrophic olivary degeneration is a rare condition caused by damage within the triangle of Guillain and Mollaret. We describe a clinical case where this occurred and discuss the anatomical, radiological and clinical history of this rare condition.

CASE SUMMARY

A 32-year-old female presented with sub-acute headache, photophobia, and dizziness. Magnetic resonance imaging revealed a 12.1 × 11 × 7.3 mm lesion arising from the floor of the fourth ventricle [ Figure 1 ]. The tumor – a choroid plexus papilloma – was completely resected through a posterior fossa craniotomy. Initially, she was asymptomatic but then developed occasional palatal myoclonus and oscillopsia. Postoperative imaging demonstrated unilateral hypertrophic olivary degeneration [ Figure 2a and b ].


Figure 1:

Axial T2 FLAIR magnetic resonance image showing fourth ventricular lesion

 

Figure 2:

(a) Axial T2-weighted magnetic resonance image showing signal increase in the anterior medulla oblongata (more pronounced on the left) consistent with hypertrophic olivary degeneration. (b) Coronal T2 FLAIR magnetic resonance image showing hyperintensity over the region of the inferior olivary nucleus.

 

DISCUSSION

Hypertrophic olivary degeneration is a rare condition caused by damage within the triangle of Guillain and Mollaret.[ 4 , 5 ] The olivary nucleus receives efferents from the ipsilateral red nucleus, which, in turn, receives efferents from the contralateral dentate nucleus through the superior cerebellar peduncle.[ 1 , 3 ] The decussating fibers from the inferior olivary nucleus terminate at the original dentate nucleus [ Figure 3a and b ]. The inferior olive gives rise to all the “climbing fibers” innervating the purkinje cells. Damage to the connections between the red nucleus and the contralateral dentate nucleus or between the red nucleus and the ipsilateral inferior olivary nucleus cause trans synaptic degeneration and interruption of the afferent input to the olivary nucleus.[ 1 , 2 , 5 ] The resulting loss of inhibition within this bidirectional and coupled “feedback loop” leads to hypertrophy of the nucleus before atrophy.[ 1 ] Damage to the olivodentate tracts does not produce the same hypertrophy of the olivary nucleus, rather this results in cerebellar atrophy.[ 2 , 3 ]


Figure 3:

(a) Coronal T2 FLAIR magnetic resonance image showing schematic of triangle of Guillain-Mollaret. (b) Axial T2 magnetic resonance image at the level of the dentate nucleus and inferior/ middle cerebellar peduncles.

 

Olivary hypertrophy develops within 6 months of the initial event and resolves within 3–4 years.[ 2 , 3 ] It is most commonly a unilateral phenomenon ipsilateral to the side of the original insult when this is within the brainstem, contralateral if the original insult is cerebellar. Rarely, bilateral hypertrophic Olivary degeneration can occur where decussating fibers from both olivary nuclei are involved.[ 3 ]

The most common clinical presentation is of palatal or oculopalatal myoclonus, weeks to months after the initial insult.[ 1 - 5 ] For those patients who have had surgery, the occurrence of new symptoms may raise concerns about a recurrence of the original pathology. For those patients who have had brain stem strokes, the occurrence of new symptoms may lead to rapid repeat assessment with a view to thrombolysis or thrombectomy. In both instances, detailed brainstem imaging is required to confirm the presence of the hypertrophic olivary nucleus and the pathological process involved. Presentation of this condition differs from Multi system atrophy diseases and olivopontocerebellar atrophy, where a more global ataxia is characteristically part of the presenting signs and symptoms. An awareness of this complication of past insults to the brain stem is of importance to all clinical neuroscience to prevent misdiagnosis with the occurrence of new symptoms.

CONCLUSION

This case provides an opportunity to review clinical anatomy, radiological change and neurology, and is an interesting illustration of a rare complication of fourth ventricular surgery. It demonstrates the intricacy of brainstem function and the variable relationship between radiological hypertrophy of the olivary nucleus and clinical symptoms, providing an important reminder of key functional anatomy and pathology.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

1. Cosentino C, Velez M, Nuñez Y, Palomino H, Quispe D, Flores M. Bilateral hypertrophic olivary degeneration and holmes tremor without palatal tremor: An unusual association. Tremor Other Hyperkinet Mov (N Y). 2016. 6: 400

2. Goyal M, Versnick E, Tuite P, Cyr JS, Kucharczyk W, Montanera W. Hypertrophic olivary degeneration: Metaanalysis of the temporal evolution of MR findings. AJNR Am J Neuroradiol. 2000. 21: 1073-7

3. Khoyratty F, Wilson T. The dentato-rubro-olivary tract: Clinical dimension of this anatomical pathway. Case Rep Otolaryngol. 2013. 2013: 934386

4. Manzano-Lopez Gonzalez D, Conesa Bertran G, Lafuente Baraza J. Unusual case of posterior fossa syndrome and bilateral hypertrophic olivary degeneration after surgical removal of a large fourth ventricle ependymoma in an adult. Acta Neurochir (Wien). 2015. 157: 1271-3

5. Martins WA, Marrone LC, Soder RB, da Costa JC. Hypertrophic olivary degeneration: Unveiling the triangle of Guillain-Mollaret. Arq Neuropsiquiatr. 2016. 74: 426-7

1 Comments

    avtar image
    Ellen Tribuci

    Posted January 5, 2023, 7:08 am

    Hi. I think this is the first article I found about Guillain Mollaret, that my mom was diagnosed in 2018, and at that time, we didn´t have anything to understand.
    In this study or even in this forum, is there some treatment for this? Even to avoid the degeneration that affects her balance, could stop or even return to normal?
    I would appreciate it if someone could give me some hope because it seems that it starting to be more complicated for her to walk alone.

    Reply

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