Superficial siderosis

[Secondary superficial siderosis of the central nervous system: report of three cases]

BACKGROUND

Superficial siderosis (SS) is an under-recognized entity. It is due to repeated microhemorrhages in the subarachnoid spaces resulting in a deposit of hemosiderin at the surface of the central nervous system and/or the cranial nerves. The origin of microhemorrhages remains unknown in almost one third of cases and therefore no treatment can be recommended. Through a literature review and new observations, our goal is to detail the outcome of patients with a recognized etiology of SS and treated surgically.

METHODS

Series of three cases and review of the literature.

RESULTS

We present three patients with symptomatic SS for whom the origin of microhemorrhages was found. The first two patients complained of longstanding ataxia and neurosensory deafness while the third patient presented with urinary retention, vertigo, diplopia and facial paresis. Neuroradiological explorations revealed a left temporoparietal cavernoma, a fronto-orbital arterio-venous malformation and a cauda equina myxopapillary ependymoma respectively. Surgical resection of the source of hemorrhage was performed in all cases. All outcomes were good with improvement of their SS-related symptoms. These cases are discussed and the current literature is reviewed.

CONCLUSION

It is important to recognize SS since the treatment of the bleeding source may prevent further deterioration and may even in some cases improve the clinical condition.

Superficial siderosis revealed by isolated cognitive impairment

Superficial siderosis (SS) is a rare disorder due to chronic bleeding into the subarachnoid or intraventricular space. The most common clinical presentation is progressive ataxia and hearing loss. The authors report two patients who presented with dementia as the primary manifestation of SS. The cognitive impairment marked by cortical frontotemporoparietal dysfunction was consistent with the pattern of signal abnormalities seen on brain magnetic resonance imaging (MRI). Diagnosis of SS must be considered when T2*-weighted MRI shows typical signal hypointensity outlining the brain and spinal cord surfaces. Performing such MRI sequences appears to be of particular interest in the context of dementia etiological diagnosis.

Unsuccessful cochlear implantation in two patients with superficial siderosis of the central nervous system

OBJECTIVE

To highlight the potential adverse outcomes with cochlear implantation (CI) in patients with superficial siderosis.

PATIENTS

Two patients with superficial siderosis of the central nervous system with secondary sensorineural hearing loss.

INTERVENTION

Cochlear implantation.

MAIN OUTCOME MEASURE

Postimplantation speech discrimination scores.

RESULTS

In both cases, initial results after implantation were promising. However, in 1 case, their ability to use the CI rapidly declined after 1 week because of major difficulties adapting to electrical stimulation. For the other case, hearing rapidly declined over a 6-month period.

CONCLUSION

The 2 patients reported did not benefit from CI in superficial siderosis that is in contrast to several previously published cases. Adequate counseling of patients with superficial siderosis is important when considering cochlear implantation as results are variable.

Localization of a rapid CSF leak with digital subtraction myelography

A 53-year-old woman with superficial siderosis underwent spinal MR imaging, which demonstrated a large cervicothoracic epidural fluid collection compatible with a CSF leak. Conventional and dynamic CT myelography failed to localize the dural tear because of rapid equilibration of myelographic contrast between the thecal sac and the extradural collection. The superior temporal resolution of digital subtraction myelography precisely localized the CSF leak preoperatively and led to the successful surgical correction of the dural tear.

The pathology of superficial siderosis of the central nervous system

Chronic or intermittent extravasations of blood into the subarachnoid space, and dissemination of heme by circulating cerebrospinal fluid, are the only established causes of superficial siderosis of the central nervous system (CNS). We studied the autopsy tissues of nine patients by iron histochemistry, immunocytochemistry, single- and double-label immunofluorescence, electron microscopy of ferritin, and high-definition X-ray fluorescence. In one case, frozen brain tissue was available for quantitative assay of total iron and ferritin. Siderotic tissues showed extensive deposits of iron and ferritin, and infiltration of the cerebellar cortex was especially severe. In addition to perivascular collections of hemosiderin-laden macrophages, affected tissues displayed iron-positive anuclear foamy structures in the neuropil that resembled axonal spheroids. They were especially abundant in eighth cranial nerves and spinal cord. Double-label immunofluorescence of the foamy structures showed co-localization of neurofilament protein and ferritin but comparable merged images of myelin-basic protein and ferritin, and ultrastructural visualization of ferritin, did not allow the conclusion that axonopathy was simply due to dilatation and rupture of fibers. Heme-oxygenase-1 (HO-1) immunoreactivity persisted in macrophages of siderotic cerebellar folia. Siderosis caused a large increase in total CNS iron but high-definition X-ray fluorescence of embedded tissue blocks excluded the accumulation of other metals. Holoferritin levels greatly exceeded the degree of iron accumulation. The susceptibility of the cerebellar cortex is likely due to Bergmann glia that serve as conduits for heme; and the abundance of microglia. Both cell types biosynthesize HO-1 and ferritin in response to heme. The eighth cranial nerves are susceptible because they consist of CNS axons, myelin, and neuroglial tissue along their subarachnoid course. The persistence of HO-1 protein implies continuous exposure of CNS to free heme or an excessively sensitive transcriptional response of the HO-1 gene. The conversion of heme iron to hemosiderin probably involves both translational and transcriptional activation of ferritin biosynthesis.

THE DEVELOPMENT OF RING-SHAPED CONTRAST ENHANCEMENT IN A CASE OF CEREBELLAR DYSEMBRYOPLASTIC NEUROEPITHELIAL TUMOR

OBJECTIVE

Dysembryoplastic neuroepithelial tumor (DNT) occurs rarely in the cerebellum. We describe a rare case of cerebellar DNT that developed contrast enhancement after long-term observation and discuss the underlying mechanism and clinical relevance of this unusual phenomenon.

CLINICAL PRESENTATION

A 34-year-old woman with known cystic cerebellar lesions presented with increased frequency of vertigo and new onset of truncal ataxia. Magnetic resonance imaging revealed new contrast enhancement in the dominant cystic lesion of the cerebellar vermis without any change in size and shape or evidence of edema.

INTERVENTION

The lesions were resected under magnetic resonance imaging guidance. Histological assessment revealed populations of small, round cells in a microcystic background containing “floating” neurons, diagnostic of DNT. Microvascular proliferation and pigmented neurons were also present.

CONCLUSION

This is the first report of the development of contrast enhancement in a previously nonenhancing case of cerebellar DNT. The acquisition of ring-shaped contrast enhancement may be associated with microvascular proliferation, but otherwise no evidence of malignant progression. In addition, this case presents the novel pathological finding of pigmented neurons in DNT.

Secondary intracranial hypertension with acute intracranial pressure crisis in superficial siderosis

Superficial siderosis of the central nervous system is a very rare disease related to hemosiderin deposits in the brain, brainstem, cerebellum and spinal cord due to chronic subarachnoid hemorrhage. Chronic increased intracranial pressure develops in about one-third of affected cases. We report a patient with superficial siderosis and sudden intracranial pressure crisis. A 29-year-old man experienced a subacute episode of headache, tinnitus and blurred vision. Magnetic resonance imaging of the brain revealed hemosiderin deposits characteristic of superficial siderosis. Extensive diagnostic work-up excluded causative pathologies of bleeding. Lumbar puncture and continuous intra-ventricular cerebrospinal fluid (CSF) pressure monitoring revealed continuous CSF pressure increase. Implantation of a ventriculo-peritoneal shunt led to complete clinical recovery. Our case emphasizes that patients with superficial siderosis may present with sudden elevation of intracranial pressure due to chronic intracranial hypertension. In this situation permanent CSF drainage provides a useful therapeutic option.

Hyperphosphorylation of tau protein in superficial CNS siderosis

In superficial CNS siderosis chronic subarachnoidal hemorrhage leads to hemosiderin deposits in the subpial layers of the brain and spinal cord. Many years usually pass between the initial event causing chronic bleedings and the development of cerebellar ataxia, sensory hearing loss and various sensorimotor deficits. The only therapeutic option is to identify and eliminate the bleeding source. Otherwise slow relentless decline to a bedridden state and dementia is usually unavoidable. However, it is not known how precisely leptomeningeal hemosiderin deposits induce progressive neurodegeneration. Here we present the first report of a patient with superficial CNS siderosis in whom cerebrospinal fluid biomarkers of brain damage were assessed. Levels of neurofilament light protein, glial fibrillary acidic protein, total tau protein and, most importantly, hyperphosphorylated tau protein were increased. The results indicate that in superficial CNS siderosis neurodegeneration may be secondary to iron toxicity and oxidative stress. Similar mechanisms have been suggested for other neurodegenerative disorders such as Alzheimer's disease.

A series of patients with subpial hemorrhage: clinical manifestation, neuroradiological presentation and therapeutic implications

Subpial hemorrhage is a rare finding in patients with a variable spectrum of neurological symptoms and signs. Here we present a series of 10 patients with subpial hemorrhage, 53 to 80 years old, diagnosed and treated within the last 4 years at a single center. Patients were identified based on imaging criteria with either magnetic resonance imaging (MRI) or computed tomography (CT) showing blood along the cortical surface. Presenting symptoms were diverse, with seizures being the most frequent followed by headaches and focal neurological signs such as sensory or motor deficits. Of 7 patients undergoing lumbar puncture, none showed fresh blood or cerebrospinal fluid (CSF) xanthochromia. Neither digital subtraction angiography (DSA) nor MR venography (MRV) confirmed cerebral vein thrombosis as a possible etiologic factor for subpial hemorrhage. Patients for whom follow-up was available (n=8), showed complete recovery indicating an excellent prognosis. Overall, the etiology of subpial hemorrhage remains obscure. Treatment should be symptomatic with particular attention to antiepileptic medication.

[Superficial hemosiderosis of the central nervous system improved by corticosteroids]

INTRODUCTION

Superficial siderosis is of the Central Nervous System (CNS) is an uncommon and often disabling disorder. There is no evidence that any treatment, including removal of an identified source of bleeding, affects disease progression.

OBSERVATION

We report the case of a 49-year-old woman exhibiting progressive and various neurological disorders associating chorea, pyramidal syndrome, cerebellar ataxia, cognitive disorders and cranial nerve deficits. She had a prior history of right occipital arterioveinous malformation (AVM) revealed four years before by ventricular hemorrhage. The AVM was treated by radiosurgery. Because of a pronounced progression of the symptoms, treatment with steroid therapy was initiated before the diagnosis of siderosis of the central nervous system was asserted by magnetic resonance imaging (rim of hypo-intensity due to hemosiderin around the brainstem, the cerebellum and the spinal cord on T-2 weighted and gradient echo T-2* imaging) and cerebrospinal fluid (CSF) examination (high CSF levels of iron and ferritin). Over the next months the neurological condition improved under steroid therapy.

CONCLUSION

Our observation is interesting because of the chorea movement disorders which are rarely reported in the disease and because of the improvement of the neurological condition after steroid therapy which is described in only another case in the literature. Steroid therapy could constitute a new track for the treatment of siderosis of CNS.

Subarachnoid hemosiderosis and superficial cortical hemosiderosis in cerebral amyloid angiopathy

Cerebral amyloid angiopathy (CAA) is an important cause of intracerebral hemorrhage. Its definite diagnosis still requires histopathologic demonstration of vascular amyloid. Thus, further improvement of noninvasive imaging methods would be desirable. Here we present 3 patients with histologically proved CAA, in which superficial cortical hemosiderosis and subarachnoid hemosiderosis were present in T2*-weighted MR images. Thus, we propose that these 2 findings might be valuable as noninvasive diagnostic markers for CAA.

Superficial siderosis: a case report and review of the literature

BACKGROUND

A 48-year-old man with a past history of a car-accident-induced coma at the age of 3 years and spontaneous bilateral subdural hematomas at the age of 34 years presented with a 2-year history of worsening gait difficulties, clumsiness and dysarthria. CT scans of the brain taken during the 6 months leading up to his presentation had revealed chronic subarachnoid hemorrhage, but angiograms had not been able to identify the source of bleeding.

INVESTIGATIONS

Neurological examination, brain MRI scan, lumbar puncture, four-vessel cerebral angiogram and spinal angiogram.

DIAGNOSIS

Superficial siderosis; a complete review of the current literature on the condition is provided.

MANAGEMENT

Iron chelating agents.