Isolated Hypoglossal Nerve Palsy as an Early Symptom of a Granular Cell Tumor.

BACKGROUND: Hypoglossal nerve palsy (HNP) is rather common as a neurological disease. However, as an isolated nerve palsy it is an exceedingly rare phenomenon and points at local pathologies along the peripheral course of the nerve. In this communication we report a granular cell tumor (GCT) arising in the submandibular segment of the hypoglossal nerve. CASE-REPORT: Spontaneous isolated HNP was recognized in a female patient. First line MR-imaging identified a clivus-chordoma. However, involvement of the hypoglossal nerve was highly unlikely according to MR-findings. Finally, ultrasonographic investigation revealed a small submandibular mass which, at histological examination, turned out to be a granular cell tumor arising within the hypoglossal nerve. CONCLUSIONS: This is the report of an extremely rare GCT originating within the 12th cranial nerve. The case illustrates that isolated motoric cranial nerve palsy may result from this rare tumor entity. This report also points out the diagnostic value of a simple ultrasonographic investigation to depict pathologic lesions of the submandibular space.

Rho-associated protein kinase 2 (ROCK2): a new target of autoimmunity in paraneoplastic encephalitis.

Onconeural antibodies are associated with cancer and paraneoplastic encephalitis. While their pathogenic role is still largely unknown, their high diagnostic value is undisputed. In this study we describe the discovery of a novel target of autoimmunity in an index case of paraneoplastic encephalitis associated with urogenital cancer.A 75-year-old man with a history of invasive bladder carcinoma 6 years ago with multiple recurrences and a newly discovered renal cell carcinoma presented with seizures and progressive cognitive decline followed by super-refractory status epilepticus. Clinical and ancillary findings including brain biopsy suggested paraneoplastic encephalitis. Immunohistochemistry of the brain biopsy was used to characterize the inflammatory response. Indirect immunofluorescence assay (IFA) was used for autoantibody screening. The autoantigen was identified by histo-immunoprecipitation and mass spectrometry and was validated by expressing the recombinant antigen in HEK293 cells and neutralization tests. Sera from 125 control patients were screened using IFA to test for the novel autoantibodies.IFA analysis of serum revealed a novel autoantibody against brain tissue. An intracellular enzyme, Rho-associated protein kinase 2 (ROCK2), was identified as target-antigen. ROCK2 was expressed in affected brain tissue and archival bladder tumor samples of this patient. Brain histopathology revealed appositions of cytotoxic CD8+ T cells on ROCK2-positive neurons. ROCK2 antibodies were not found in the sera of 20 patients with bladder cancer and 17 with renal cancer, both without neurological symptoms, 49 healthy controls, and 39 patients with other antineuronal autoantibodies. In conclusion, novel onconeural antibodies targeting ROCK2 are associated with paraneoplastic encephalitis and should be screened for when paraneoplastic neurological syndromes, especially in patients with urogenital cancers, occur.

Postoperative neuroimaging analysis of DRT deep brain stimulation revision surgery for complicated essential tremor.

BACKGROUND: We report a patient who received conventional bilateral deep brain stimulation of the ventral intermediate nucleus of thalamus (Vim) for the treatment of medication refractory essential tremor (ET). After initial beneficial effects, therapeutic efficacy was lost due to a loss of control of his proximal trunkal and extremity tremor. The patient received successful diffusion tensor magnetic resonance imaging fiber tractographic (DTI FT)-assisted DBS revision surgery targeting the dentato-rubro-thalamic tract (DRT) in the subthalamic region (STR). OBJECTIVE: To report the concept of DTI FT-assisted DRT DBS revision surgery for ET and to show sophisticated postoperative neuroimaging analysis explaining improved symptom control. METHODS: Analysis was based on preoperative DTI sequences and postoperative helical computed tomography (hCT). Leads, stimulation fields, and fibers were reconstructed using commercial software systems (Elements, Brainlab AG, Feldkirchen, Germany; GUIDE XT, Boston Scientific Corp., Boston, MA, USA). RESULTS: The patient showed immediate and sustained tremor improvement after DTI FT-assisted revision surgery. Analysis of the two implantations (electrode positions in both instances) revealed a lateral and posterior shift in the pattern of modulation of the cortical fiber pathway projection after revision surgery as compared to initial implantation, explaining a more efficacious stimulation. CONCLUSIONS: Our work underpins a possible superiority of direct targeting approaches using advanced neuroimaging technologies to perform personalized DBS surgery. The evaluation of DBS electrode positions with the herein-described neuroimaging simulation technologies will likely improve targeting and revision strategies. Direct targeting with DTI FT-assisted approaches in a variety of indications is the focus of our ongoing research.

Is postoperative encephalopathy with choreoathetosis an acquired form of neuroacanthocytosis?

Postoperative encephalopathy with choreoathetosis ("postpump chorea") is a rare complication of open-heart surgery and, in particular, the employment of a cardiopulmonary bypass pump. It almost exclusively occurs in young children. While risk factors and the underlying histopathology have been identified, the pathogenesis of postpump chorea, crucially, remains largely unknown. Transient cerebral hypoperfusion associated with cardiopulmonary bypass is considered a likely candidate mechanism, but the evidence is insufficient and inconclusive. It is hypothesized in this article, that postpump chorea may be caused by mechanical trauma to red blood cells and resulting acanthocytosis. These dysfunctional erythrocytes could then lead to damage to the globus pallidus and disease development akin to that presumed in neuroacanthocytosis. In patients with neuroacanthocytosis an association between acanthocytosis and basal ganglia pathology has been suggested. To test the mechanism hypothesized here, the effects of cardiopulmonary bypass on erythrocyte morphology and function could be systematically tested in children undergoing cardiac surgery. Ideally, the extent of erythrocyte damage could be correlated with the risk of developing postpump chorea. Finally, if the proposed hypothesis is supported by empirical findings, efforts to reduce blood cell damage during extracorporeal circulation in children might prevent this devastating complication.

Immunoglobulin-G4-related hypertrophic pachymeningitis with antineutrophil cytoplasmatic antibodies effectively treated with rituximab.

We describe a 52-year-old man with hypertrophic pachymeningitis (HP) who was both seropositive for antineutrophil cytoplasmatic antibodies (ANCA) against myeloperoxidase, and had an immunoglobulin G4 (IgG4) positive fibroinflammatory response in meningeal biopsy. HP is a chronic inflammatory thickening of the dura mater which typically presents with headache, cranial nerve dysfunction and other neurological deficits. While first-line treatment with corticosteroids is recommended, many patients relapse and need additional immunosuppression. One recently described etiology is IgG4-related disease and in a subgroup of idiopathic patients, evidence suggests a crucial role of ANCA. To our knowledge, the simultaneous occurrence of IgG4-related disease and ANCA has not been reported so far. This man suffered life-threatening disease progression despite the administration of high dose steroids, cyclophosphamide and azathioprine. Treatment with rituximab was initiated which led to disappearance of clinical symptoms and decrease of dural thickening within weeks. This patient presents a possible disease overlap of IgG4-related and ANCA-associated HP and illustrates the effectiveness of rituximab in refractory IgG4-related HP.

Mechanical thrombectomy - an alternative treatment option in a patient with acute ischemic stroke and multiple contraindications for systemic thrombolysis: a case report.

INTRODUCTION: Acute ischemic stroke is a common cause of disability and death in developed countries. Standard therapy for patients who present within 4.5 hours from the onset of symptoms is intravenous thrombolysis if contraindications such as oral anticoagulation, cancer or recent surgery are ruled out. Apart from that, mechanical recanalization is a new treatment option for patients with occlusion of major cerebral arteries as a cause of ischemic stroke. CASE PRESENTATION: In this case report we describe a 55-year-old Caucasian man with a right hemispheric ischemic syndrome who presented in time but who had multiple contraindications against systemic thrombolysis. He was then treated with mechanical recanalization and recovered. On discharge from the hospital he had only a slight left-sided facial paresis and discrete impairment of motion smoothness in his left hand. CONCLUSION: We conclude that multimodal imaging should be performed in all patients with an acute onset of neurological symptoms suspicious of ischemic stroke, even if they have contraindications against an intravenous thrombolytic treatment.

Novel APP/Aß mutation K16N produces highly toxic heteromeric Aß oligomers.

Here, we describe a novel missense mutation in the amyloid precursor protein (APP) causing a lysine-to-asparagine substitution at position 687 (APP770; herein, referred to as K16N according to amyloid-ß (Aß) numbering) resulting in an early onset dementia with an autosomal dominant inheritance pattern. The K16N mutation is located exactly at the α-secretase cleavage site and influences both APP and Aß. First, due to the K16N mutation APP secretion is affected and a higher amount of Aß peptides is being produced. Second, Aß peptides carrying the K16N mutation are unique in that the peptide itself is not harmful to neuronal cells. Severe toxicity, however, is evident upon equimolar mixture of wt and mutant peptides, mimicking the heterozygous state of the subject. Furthermore, Aß42 K16N inhibits fibril formation of Aß42 wild-type. Even more, Aß42 K16N peptides are protected against clearance activity by the major Aß-degrading enzyme neprilysin. Thus the mutation characterized here harbours a combination of risk factors that synergistically may contribute to the development of early onset Alzheimer disease.