Hypertrophic olivary degeneration following surgical excision of brainstem cavernous hemangioma: a case report

The dentato-rubro-olivary pathway revisited: New MR imaging observations regarding hypertrophic olivary degeneration

Hypertrophic olivary degeneration (HOD) following a lesion of the dentato-rubro-olivary pathway (DROP) is a well-known imaging finding and has extensively been described in the recent literature. We reviewed our patients with HOD as a result of a lesion of the DROP in order to analyze the disruption of the DROP and the resulting HOD in comparison with the literature. We observed unusual imaging findings in four patients. In two patients it concerned new observations related to the timing and imaging appearances of HOD. HOD became only visible 6 years after a lesion in the red nucleus in one patient and a cystic degeneration of the olivary nucleus was seen 3 years after the HOD in a second patient. In two patients we found HOD that could only be explained by the existence of an afferent feedback loop between the dentate nucleus and the inferior olivary nucleus and by the knowledge that these fibers run through the ipsilateral olivary nucleus before ending in the contralateral olivary nucleus. In one of these patients the lesion was located in the inferior cerebellar peduncle. In the other patient the lesion was located on the midline in the medulla oblongata. The imaging findings in these patients reveal new observations in the stages of imaging appearances in HOD and shed light on the forgotten dentato-olivary afferent feedback loop of the DROP. Clin. Anat. 30:543-549, 2017. © 2017 Wiley Periodicals, Inc.

Hypertrophic olivary degeneration and cerebrovascular disease: movement in a triangle

Hypertrophic olivary degeneration is a rare kind of trans-synaptic degeneration that occurs after lesions of the dentatorubro-olivary pathway. The lesions, commonly unilateral, may result from hemorrhage due to vascular malformation, trauma, surgical intervention or hypertension, tumor, or ischemia. Bilateral cases are extremely rare. This condition is classically associated with development of palatal tremor, but clinical manifestations can include other involuntary movements. We describe 2 cases: unilateral hypertrophic olivary degeneration in a 60-year-old man with contralateral athetosis and neurologic worsening developing several years after a pontine hemorrhage and bilateral hypertrophic olivary degeneration in a 77-year-old woman with development of palatal tremor, probably secondary to pontine ischemic lesions (small vessel disease).

Cavernous malformation of brainstem, thalamus, and basal ganglia: a series of 176 patients

BACKGROUND

Cavernous malformations (CMs) in deep locations account for 9% to 35% of brain malformations and are surgically challenging.

OBJECTIVE

To study the clinical features and outcomes following surgery for deep CMs and the complication of hypertrophic olivary degeneration (HOD).

METHODS

Clinical records, radiological findings, operative details, and complications of 176 patients with deep CMs were reviewed retrospectively.

RESULTS

Of 176 patients with 179 CMs, 136 CMs were in the brainstem, 27 in the basal ganglia, and 16 in the thalamus. Cranial nerve deficits (51.1%), hemiparesis (40.9%), numbness (34.7%), and cerebellar symptoms (38.6%) presented most commonly. Hemorrhage presented in 172 patients (70 single, 102 multiple). The annual retrospective hemorrhage rate was 5.1% (assuming CMs are congenital with uniform hemorrhage risk throughout life); the rebleed rate was 31.5%/patient per year. Surgical approach depended on the proximity of the CM to the pial or ependymal surface. Postoperatively, 121 patients (68.8%) had no new neurological deficits. Follow-up occurred in 170 patients. Delayed postoperative HOD developed in 9/134 (6.7%) patients with brainstem CMs. HOD occurred predominantly following surgery for pontine CMs (9/10 patients). Three patients with HOD had palatal myoclonus, nystagmus, and oscillopsia, whereas 1 patient each had limb tremor and hemiballismus. At follow-up, 105 patients (61.8%) improved, 44 (25.9%) were unchanged, and 19 (11.2%) worsened neurologically. Good preoperative modified Rankin Score (98.2% vs 54.5%, P = .001) and single hemorrhage (89% vs 77.3%, P < .05) were predictive of good long-term outcome.

CONCLUSION

Symptomatic deep CMs can be resected with acceptable morbidity and outcomes. Good preoperative modified Rankin Score and single hemorrhage are predictors of good long-term outcome.

Hypertrophic olivary degeneration after surgical resection of brain tumors

BACKGROUND

Hypertrophic olivary degeneration (HOD) can be seen as high signal intensity with enlargement of the inferior olivary nucleus (ION) on T2-weighted magnetic resonance (MR) images 4-6 months after injury of the Guillain-Mollaret triangle. To the best of our knowledge, there has been no systematic evaluation with regard to the relationship between neurosurgical intervention affecting this pathway and the appearance of HOD.

PURPOSE

To evaluate MR findings of HOD after surgical resection of brain tumors with the temporal evolution in focus.

MATERIAL AND METHODS

MR images of seven patients that showed signal changes in the ION after surgical resection of brain tumors in the posterior fossa were retrospectively reviewed. T1-weighted imaging with and without gadolinium (Gd) contrast enhancement and T2-weighted imaging were performed in all patients before and after surgery.

RESULTS

Before surgery, no patient had a signal change in the ION. T2-high signal intensity of the ION initially appeared 5 days to 2.5 months after surgery. Five patients showed enlargement of the ION with T2-high signal intensity 11 days to 3.5 months after surgery: three patients showed the enlargement of the ION subsequent to the T2-signal change on serial follow-up MR images. On Gd-enhanced T1-weighted images, there was no enhancement at the ION in any patient. Each signal change of the ION was consistent with HOD, according to the relationship between the resection site of the tumor and the Guillain-Mollaret triangle on follow-up MRI.

CONCLUSION

HOD can be caused after neurosurgical intervention of brain tumors involving the Guillain-Mollaret triangle. It is important for radiologists to distinguish HOD from tumor recurrence.

Hypertrophic olivary degeneration following surgical resection or gamma knife radiosurgery of brainstem cavernous malformations: an 11-case series and a review of literature

BACKGROUND

We describe 11 patients with hypertrophic olivary degeneration (HOD) after surgical resection or gamma knife radiosurgery for brainstem cavernous malformations. In addition, we statistically analyzed the predicting factors associated with the development of HOD.

METHODS

From January 2001 to May 2011, a total of 73 patients (30 in the surgical group and 43 in the radiosurgery group) with brainstem cavernous malformations were treated in our institute. Of them, 11 patients (incidence: 15 %) developed HOD with high signal intensity on T2-weighted MRI during follow-up. The predicting factors (location, size, age, and treatment method) associated with the development of HOD were statistically analyzed.

RESULTS

Among the 11 HOD patients, seven patients received surgical resection and four patients received gamma knife radiosurgery. Six patients had bilateral HOD and the remaining five patients had unilateral HOD. Overall HOD-associated symptoms presented in four patients, including three palatal tremors and one ataxia. In all four patients with symptoms, these symptoms disappeared incompletely within the clinical follow-up period. The size of the cavernous malformation, age of patient, and treatment methods were not significantly correlated with the development of HOD. A significantly higher incidence of HOD was associated with midbrain cavernous malformations than with pontine or medulla cavernous malformations.

CONCLUSIONS

HOD should be recognized as a non-infrequent complication of surgical resection or gamma knife radiosurgery within the brainstem, especially for midbrain cavernous malformations. In addition, to the best of our knowledge, this is the first report on HOD development after radiosurgery.

Bilateral hypertrophic olivary degeneration in Wilson disease

Hypertrophic olivary degeneration resulting from lesions of the dento-rubro-olivary pathway, also called Guillain-Mollaret-triangle, has been described previously in a number of cases. Reports about bilateral hypertrophic olivary degeneration of the inferior olivary nuclei are very limited, and the magnetic resonance imaging findings of hypertrophic olivary degeneration in Wilson disease have not yet been described to the best of our knowledge. Herein, we present the first report of bilateral hypertrophic olivary degeneration diagnosed by magnetic resonance imaging in a patient suffering from Wilson disease.

Differential diagnosis of T2 hyperintense brainstem lesions: Part 1. Focal lesions

Brainstem lesions can be classified as focal or diffuse. Magnetic resonance imaging is the most suitable imaging modality for evaluating these lesions. As a rule, focal lesions are not large and have well-defined margins. Causes include tumors, vascular malformations, demyelinating diseases, brain abscesses, hypertrophic olivary degeneration, and dilated Virchow-Robin spaces. Differential diagnoses of these numerous entities mandates a review of magnetic resonance imaging findings in conjunction with epidemiologic aspects, clinical features, and other medical test results.

Diffusion tensor imaging in hypertrophic olivary degeneration

SUMMARY

We report DTI and fiber tractography findings in a case of hypertrophic olivary degeneration. A 51-year-old man presented with an abnormal gait and visual difficulties. MR imaging showed enlargement of the right medullary olive and a vascular lesion in the right pontine tegmentum. Fiber tractography showed decreased volume of the right central tegmental tract, supporting a diagnosis of HOD.

Hypertrophic olivary degeneration after surgical removal of cavernous malformations of the brain stem: report of four cases and review of the literature

BACKGROUND

Hypertrophic olivary degeneration (HOD) is a pathological phenomenon that occurs after injury to the dentato-olivary pathway. Its hallmarks include hypertrophy of the olive with increased T2 signal intensity on magnetic resonance imaging, and it often manifests with palatal tremor and oscillopsia clinically.

METHOD

We report the cases of four patients who developed delayed HOD after surgical resection of pontine lesions.

FINDINGS

We discuss the anatomical and pathological details of this disease and review the few other reported cases of HOD after resection of lesions within the brainstem.

CONCLUSIONS

HOD should be recognized as a possible complication of surgery within the brainstem and must be diagnosed promptly so that patients can be appropriately counseled and symptoms can be treated.

Hypertrophic olivary degeneration after resection of a cerebellar tumor

We report a case of hypertrophic olivary degeneration due to cerebellar surgery for a low-grade tumor. A 27-year-old female presented with right-sided paresthesias and intermittent leg paresis following a right cerebellar resection of a tumor 2 weeks prior. One month later, her symptoms remained stable while her neurological examination demonstrated slight right hemi-body hypoesthesia and subtle appendicular ataxia in her right upper extremity. An MRI scan revealed a hypertrophied left anterolateral medulla with increased T2 signal and no diffusion abnormality. The T2 hyperintensity and hypertrophy slowly resolved and she clinically improved without further intervention. Hypertrophic olivary degeneration may be mistaken for tumor progression, post-operative vasculopathy or granulation tissue and should be considered in patients undergoing cerebellar surgery.

Dégénérescence olivaire hypertrophique

PURPOSE

to describe the magnetic resonance imaging features of hypertrophic olivary degeneration (HOD) subsequent to lesion in the "Guillain-Mollaret triangle".

MATERIALS AND METHODS

15 cases of HOD were diagnosed at MR imaging in 12 patients (4 women and 8 men) with posterior fossa lesion. The time interval from the beginning of the disease to the MR examination was 3 weeks to 8 (1/2) years. Evaluation of the changes in signal intensity over time of the lesions was available in 6 patients.

RESULTS

Nine cases of HOD were unilateral and three were bilateral. HOD was associated to a lesion of the contralateral dentate nucleus in 8 cases, to a lesion of the ipsilateral central tegmental tract in 5 cases and to a lesion of the contralateral superior cerebellar peduncle in 2 cases. Hyperintensity and hypertrophy of the olive on proton density and T2-weighted images appeared as early as 3 weeks after the ictus. A curved central hyperintensity (CCH) could be observed 7 months after the initial presentation. Decrease in the signal intensity was observed after 3 (1/2) years and abnormal signal intensity could persist for up to 13 years. Palatal myoclonus at 5 months was associated with HOD in one case.

CONCLUSION

HOD is considered a trans-synaptic degeneration subsequent to lesions in the Guillain-Mollaret triangle. Hyperintensity and hypertrophy of the olive are observed, sometimes with palatal myoclonus.