Indian Journal of Radiology Indian Journal of Radiology  

   Login   | Users online: 1389

Home Bookmark this page Print this page Email this page Small font sizeDefault font size Increase font size     


NEURORADIOLOGY Table of Contents   
Year : 2006  |  Volume : 16  |  Issue : 4  |  Page : 701-704
Hypertrophic olivary degeneration following trauma - a case report

Nijjar Scan & Diagnostic Centre, Amritsar, India

Click here for correspondence address and email

Date of Submission28-Oct-2006
Date of Acceptance20-Nov-2006


Hypertrophic Olivary degeneration (HOD) is a rare type of neuronal degeneration involving the dentatorubro-olivary pathway. It is a secondary change caused by the impairment of Guillain Mollaret triangle. We present a case of a thirty-five years old man who had head injury with MR evidence of haemorrhagic contusion at the ponto-mesencephalic junction extending into the superior cerebellar peduncle on left side. Five months after the injury he developed left upper extremity rhythmic tremor. Repeat MRI permitted visualization of hypertrophic olivary degeneration, which appeared as a characteristic high signal intensity in the right inferior olivary nucleus on T2 W and FLAIR images, with enlargement of the nucleus. The literature and imaging findings of this uncommon condition are reviewed.

Keywords: Hypertrophic Olivary, degeneration; magnetic resonance imaging

How to cite this article:
Arora V, Nijjar I S, Sandhu P S, Singh J, Abrol R, Roopa. Hypertrophic olivary degeneration following trauma - a case report. Indian J Radiol Imaging 2006;16:701-4

How to cite this URL:
Arora V, Nijjar I S, Sandhu P S, Singh J, Abrol R, Roopa. Hypertrophic olivary degeneration following trauma - a case report. Indian J Radiol Imaging [serial online] 2006 [cited 2021 Feb 25];16:701-4. Available from:

   Introduction Top

Hypertrophic olivary degeneration occurs in lesions involving the dentatorubro-olivary system [1]. A unique finding in this form of transneuronal degeneration is enlargement rather than atrophy of the affected structure. Typically, haemorrhages following a hypertensive crisis are the cause of this pathological entity [2],[3],[4]. We describe a patient in whom haemorrhagic contusion in the region of superior cerebellar peduncle and midbrain resulted in hypertrophic olivary degeneration.

   Case report Top

A thirty-five years old man was unconscious after severe head injury. His MRI revealed evidence of diffuse axonal injury with a large haemorrhagic contusion at the ponto-mesencephalic junction and left superior cerebellar peduncle, appearing hyperintense on T2 W and FLAIR images with areas of hypointensity in it [Figure - 1]. There was also evidence of subarachnoid haemorrhage seen as hyperintensity in the sulcal spaces on FLAIR images. The patient was kept on conservative management.

After five months following trauma he developed tremor of the left upper limb. The tremor was present at rest and further amplified during intentional movements. It disappeared during sleep. There was no evidence of palatal tremor.

He was referred for a repeat MRI that showed gliottic changes and haemorrhagic residue in the left superior cerebellar peduncle-sequelae of old head injury [Figure - 2]. In addition, there was hyperintense signal in the right inferior Olivary nucleus on T2 W and FLAIR images with enlargement of the nucleus [Figure - 3]. The lesion was isointense on T1 W images (not shown). Diffusion weighted images did not reveal the lesion [Figure - 4].

   Discussion Top

Hypertrophic olivary degeneration is a form of transsynaptic degeneration [3]. It represents the end result of a lesion that damages the neural connections between the dentate nucleus of the cerebellum, the red nucleus, and the inferior olivary nucleus: the dentatorubral - olivary pathway [5],[6]. It is considered a unique type of degeneration because it is associated with enlargement, rather than atrophy, of the affected structure - the inferior olivary neurons [7].

The dentatorubral - olivary connections were described by Guillain and Mollaret [6] in 1931, and this pathway is thus referred to as the Guillain Mollaret triangle. The Guillain Mollaret triangle is a triangular circuit connecting the dentate nucleus of the cerebellum of one side with the red nucleus and the inferior olivary nucleus of the other side [Figure 5]. The dentate nucleus and the contralateral red nucleus are connected by the superior cerebellar peduncle (dentatorubral tract), with fibres crossing in the decussation of the peduncle at the lower midbrain. This tract is part of the reflex arc that controls fine voluntary movements. The red nucleus and the ipsilateral inferior olivary nucleus are connected by the central tegmental tract.

[Figure 5] - Guillain Mollaret triangle.

There are three possibilities of presentation of hypertrophic olivary degeneration, ipsilateral and contralateral to the lesion, but rarely it can involve the olives bilaterally [8]. If the lesion is located in the tegmentum of the brainstem and involves the central tegmental tract, the degeneration occurs in the ipsilateral olive. If the lesion is located in a cerebellar hemisphere and involves the dentate nucleus, the olivary degeneration will be contralateral, due to the dicussation of the dentato-rubral fibres. If the lesion involves the superior cerebellar peduncle, the degeneration will occur contra-laterally, as was seen in our case. Bilateral hypertrophic ovary degeneration has also been reported [9],[10]. A paramedian lesion, if located near the peduncle, may result in bilateral hypertrophic olivary degeneration, if there is involvement of both the dentato-rubral fibres, and the central tegmental tract.

Focal brainstem insults that may lead to pathway interruption include ischaemic infarction, demyelination and haemorrhage. The latter often related to hypertensive disease or diffuse axonal injury following severe head trauma [2],[11]. Olivary hypertrophy is not seen immediately after the brainstem insult but typically appears in a delayed fashion, usually within 4-6 months. The pathologic process persists and is frequently visible after 10 months. Although olivary hypertrophy typically resolves in 10-16 months, olivary hyperintensity on T2 W images may persist for years after resolution of the hypertrophy [12],[13]. Clinical symptoms such as abnormal movement rarely improve. Olivary enlargement corresponds pathologically to an unusual vacuolar degeneration of cytoplasm that results in enlargement related in part to an increased number of astrocytes [13].

Clinical findings associated with olivary hypertrophy include the dentatorubral or Holmes' tremor, palatal myoclonus and occular myoclonus. Holmes' tremor includes an unusual combination of 2-5 Hz rest, postural and kinetic tremor of an upper extremity. It usually begins weeks to months after brainstem stroke, so compensatory or secondary changes in nervous system function must contribute to tremor genesis. Palatal tremor is a rhythmic involuntary movement that appears mainly in the soft palate. There have been few cases describing the development of palatal tremor some time after the appearance of Holmes' tremor [9],[14]. At the time of repeat MRI, our patient had Holmes' tremor but no evidence of palatal tremor.

The differential diagnosis of signal hyperintensity in the antero-lateral part of the medulla includes infarction, demyelination, tumour and inflammatory processes (tuberculosis, sarcoidosis or encephalitis). The lack of contrast enhancement, however is against many tumours or infectious entities, while the additional enlargement of the olivary nucleus is against chronic stages of infarction or multiple sclerosis [15]. Diffusion weighted study helps to rule out acute infarction. The most important clue to the diagnosis is the association of a remote lesion within the Guillain - Mollaret triangle [3].

We conclude that hypertrophic olivary degeneration is caused by various etiologies, and may present various aspects. When inferior olivary lesions, especially, hyperintensity on T2 W images and / or swelling, are recognised, it is important to investigate if the Guillain Mollaret triangle is impaired. Familiarity with the characteristic MR features and exact knowledge of this degeneration would avoid misinterpretation of hypertrophic olivary degeneration as other independent lesions such as infarction, tumour or demyelinating disease.

   References Top

1.Hirono N, Kameyama M, Kobayashi Y, et al. MR demonstration of a unilateral olivary hypertrophy caused by pontine tegmental haematoma. Neuroradiology 1990;32:340-2.   Back to cited text no. 1  [PUBMED]  
2.Kitajima M, Korogi Y, Shimomura O, et al. Hypertrophic Olivary degeneration: MR imaging and pathologic findings. Radiology 1994;192:539-43.   Back to cited text no. 2  [PUBMED]  
3.Salamon-Murayama N, Russell EJ, Rabin BM. Diagnosis please. Case 17: hypertrophic olivary degeneration secondary to pontine haemorrhage. Radiology 1999;213:814-17.   Back to cited text no. 3    
4.Suzuki M, Takashima T, Ueda F, et al. Olivary degeneration after intracranial haemorrhage or trauma: follow-up MRI. Neuroradiology 1999;41:9-12.   Back to cited text no. 4  [PUBMED]  [FULLTEXT]
5.Oppenheim H. Uber oliven degeneration bei atheromatose der basalen hinarterien . Berl Klin Wochenschr 1887;34:638-639.   Back to cited text no. 5    
6.Guillain G, Mollaret P. Deux cas de myoclonies synchrones et rhythmes velopharyngo-laryngo-oculo-diaphragmatiques. Rev Neurol 1931;2:545-566.   Back to cited text no. 6    
7.Duchen LW. General pathology of neurons and neuralgia. In: Greenfield H, Corsellis JA, Duchen LW, eds. Neuropathology. 5th ed. New York, NY: Wiley, 1994; 20-21.   Back to cited text no. 7    
8.Virzi V., Tampieri D., Weill A. and Venturi F. Hypertrophic Olivary Degeneration (HOD), Revisited. Neuro Image 2004:Vol 20 No.2: 7-8.   Back to cited text no. 8    
9.Carlos R.M. Rieder, Ricardo G. Reboucas, Marcelo P. Ferreira. Holmes tremor in association with bilateral hypertrophic olivary degeneration and palatal tremor. Chronological considerations. Arq Neuropsiquiatr 2003;61 (2-B): 473-477.   Back to cited text no. 9    
10.Gerace C, Fele M R, Luna R and Piazza G . Bilateral hypertrophic olivary degeneration. Journal of neurology,neurosurgery and psychiatry 2006: 77 (1):73-76.   Back to cited text no. 10    
11.Birbamer G, Gerstenbrand F, Aichner F, et al. MR imaging of post traumatic olivary hypertrophy, Funct. Neurol 1994;9:183-187.   Back to cited text no. 11    
12.Uchino A, Hasuo K, Uchida S, et al. Olivary degeneration after cerebellar or brainstem haemorrhage: MRI. Neuroradiology 1993;35:335-338.   Back to cited text no. 12    
13.Goto N, Kaneko M. Olivary enlargement: chronological and morphometric analysis. Acta Neuropathol (Berl) 1981; 54:275-282.   Back to cited text no. 13  [PUBMED]  
14.Masucci EF, Kurtzke JF, Saini N. Myorhythmia: a widespread movement disorder: clinicopathological correlations. Brain 1984; 107: 53-79.   Back to cited text no. 14  [PUBMED]  [FULLTEXT]
15.Krings T, Foltys H, Meister IG and Reul J. Hypertrophic olivary degeneration following pontine haemorrhage: hypertensive crisis or cavernous haemangioma bleeding? Journal of Neurology, Neurosurgery and Psychiatry 2003; 74:797-799.   Back to cited text no. 15    

Correspondence Address:
V Arora
Nijjar Scan and Diagnostic Centre, 51/1, Court Road, Amritsar-143001
Login to access the Email id

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0971-3026.32327

Rights and Permissions


  [Figure - 1], [Figure - 2], [Figure - 3], [Figure - 4]

This article has been cited by
1 MRI findings of olivary degeneration after surgery for posterior fossa tumours in children: incidence, time course and correlation with tumour grading
Tommaso Tartaglione,Giana Izzo,Andrea Alexandre,Annibale Botto,Giuseppe Maria Di Lella,Simona Gaudino,Massimo Caldarelli,Cesare Colosimo
La radiologia medica. 2015;
[Pubmed] | [DOI]
2 Bilateral hypertrophic olivary degeneration following surgical resection of a posterior fossa epidermoid cyst
Vaidhyanath, R., Thomas, A., Messios, N.
British Journal of Radiology. 2010; 83(994): 211-215
3 Bilateral hypertrophic olivary degeneration following surgical resection of a posterior fossa epidermoid cyst
R. Vaidhyanath,A. Thomas,N. Messios
British Journal of Radiology. 2010; 83(994): e211
[Pubmed] | [DOI]
4 Inferior olive hypertrophy | [Hypertrofická degenerace olivy]
Derner, M., Drugová, B., Druga, R.
Ceska Radiologie. 2009; 63(3): 232-237


    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
    Email Alert *
    Add to My List *
* Registration required (free)  

    Case report
    Article Figures

 Article Access Statistics
    PDF Downloaded428    
    Comments [Add]    
    Cited by others 4    

Recommend this journal