Presumptive isolated neurosarcoidosis involving eloquent structures: An argument for empirical TNF-α inhibition.

There are clinical and radiological phenotypes characteristic of neurosarcoidosis. Histopathologic confirmation is preferred, however, biopsy is associated with a significant risk of morbidity when only eloquent neural structures are involved and where there is no systemic disease. We present a series of patients with isolated neurosarcoidosis and suggest circumstances where an empirical, closely monitored, trial of tumour-necrosis-factor-alpha inhibitor therapy can improve outcome and diagnostic confidence.

Decoding diffusivity in multiple sclerosis: analysis of optic radiation lesional and non-lesional white matter.

OBJECTIVES: Diffusion tensor imaging (DTI) has been suggested as a new promising tool in MS that may provide greater pathological specificity than conventional MRI, helping, therefore, to elucidate disease pathogenesis and monitor therapeutic efficacy. However, the pathological substrates that underpin alterations in brain tissue diffusivity are not yet fully delineated. Tract-specific DTI analysis has previously been proposed in an attempt to alleviate this problem. Here, we extended this approach by segmenting a single tract into areas bound by seemingly similar pathological processes, which may better delineate the potential association between DTI metrics and underlying tissue damage. METHOD: Several compartments were segmented in optic radiation (OR) of 50 relapsing-remitting MS patients including T2 lesions, proximal and distal parts of fibers transected by lesion and fibers with no discernable pathology throughout the entire length of the OR. RESULTS: Asymmetry analysis between lesional and non-lesional fibers demonstrated a marked increase in Radial Diffusivity (RD), which was topographically limited to focal T2 lesions and potentially relates to the lesional myelin loss. A relative elevation of Axial Diffusivity (AD) in the distal part of the lesional fibers was observed in a distribution consistent with Wallerian degeneration, while diffusivity in the proximal portion of transected axons remained normal. A moderate, but significant elevation of RD in OR non-lesional fibers was strongly associated with the global (but not local) T2 lesion burden and is probably related to microscopic demyelination undetected by conventional MRI. CONCLUSION: This study highlights the utility of the compartmentalization approach in elucidating the pathological substrates of diffusivity and demonstrates the presence of tissue-specific patterns of altered diffusivity in MS, providing further evidence that DTI is a sensitive marker of tissue damage in both lesions and NAWM. Our results suggest that, at least within the OR, parallel and perpendicular diffusivities are affected by tissue restructuring related to distinct pathological processes.

Lhermitte-Duclos disease presenting with atypical positional nystagmus.

We describe a patient with dysplastic cerebellar gangliocytoma (Lhermitte-Duclos disease) who presented with an acute onset of positional disequilibrium. Video-oculography in the right Hallpike position revealed rightward torsional down-beat nystagmus, initially thought to be right anterior canal benign positional vertigo. However, the presence of spontaneous nystagmus, the persistent character of the positional nystagmus and the absence of fatigability indicated central positional nystagmus, attributable to his right-sided Lhermitte-Duclos disease. These findings emphasise the need for clinicians to reconsider a central cause before diagnosing the rare anterior canal benign positioning vertigo variant.

Axonal loss of retinal neurons in multiple sclerosis associated with optic radiation lesions.

OBJECTIVE: To investigate the potential links between thinning of retinal ganglion cell axons in eyes of patients with multiple sclerosis (MS) without past optic neuritis (ON) and MS-related inflammatory damage of the posterior visual pathway. METHODS: Temporal retinal nerve fiber layer (tRNFL) thickness was analyzed in eyes with no history of ON (NON) from 53 patients with relapsing-remitting MS. Fifty normal age- and sex-matched controls were examined with optical coherence tomography. Low-contrast visual acuity charts were used for functional assessment of vision. The optic tract (OT) and optic radiation (OR) were identified using probabilistic tractography, and volume of T2 fluid-attenuated inversion recovery lesions and diffusion tensor imaging (DTI) indices were measured within both structures. Cross-sectional diameter of the OT was also calculated. RESULTS: tRNFL thickness was significantly reduced in NON eyes and was associated with reduced low-contrast visual acuity. Lesions within the OR were detected in the majority of patients. There was a significant correlation between thinning of the tRNFL and OR lesion volume (adjusted for non-OR lesion volume, age, sex, and disease duration). tRNFL thickness also correlated with OR DTI indices. No OT lesions were identified in any of the patients and no relationship between retinal nerve fiber layer loss and potential markers of OT lesions was found. CONCLUSION: The results demonstrate a strong tract-specific association between loss of tRNFL fibers and MS-related inflammation within OR.

An unusual case of a pituitary fossa aspergilloma in an immunocompetent patient mimicking infiltrative tumour.

Sellar aspergillosis is a rare infection commonly mistaken for a pituitary tumour. We present a rare case of pituitary fossa Aspergillus fumigatus mycetoma in an immunocompetent 90-year-old female, who presented with headaches. Magnetic resonance imaging scans demonstrated an enhancing pituitary fossa mass that appeared to infiltrate the sphenoid sinus, suggestive of an invasive tumour. Stereotactic trans-sphenoidal resection confirmed localized A. fumigatus infection. The abscess was debrided and the dura was left intact. Her headaches resolved post-operatively and she was treated with voriconazole. This indicates that aspergilloma should be considered as a differential for an unexplained pituitary lesion even in elderly immunocompetent patients.

What lies beneath the tent? JC-virus cerebellar granule cell neuronopathy complicating sarcoidosis.

A 49-year-old, HIV-negative woman with sarcoidosis presented with a subacute unilateral cerebellar syndrome. A brain MRI revealed a hyperintense lesion without mass effect in the left cerebellar hemisphere, but no pathology above the tentorium. Steroid therapy for presumed neurosarcoidosis was ineffective and the patient deteriorated progressively. Cerebellar biopsy showed abnormal granule cells and demyelination. Immunocytochemistry confirmed the diagnosis of progressive multifocal leucoencephalopathy (PML) with JC (John Cunningham) virus granule cell neuronopathy. The patient succumbed to progressive brainstem dysfunction despite treatment with cidofovir. Although rare, PML should be considered in all patients with impaired cell-mediated immunity and unexplained neurological dysfunction, even in the absence of HIV infection.

Post-cranial irradiation syndrome with migraine-like headaches, prolonged and reversible neurological deficits and seizures.

Two adult patients with a background history of astrocytomas treated with resection and cranial irradiation, 18 and 16 years previously, presented with acute onset of headache associated with prolonged neurological deficits, including dysphasia and right hemiparesis. The first patient also developed seizures while in hospital. In both patients, magnetic resonance imaging brain scans failed to show evidence of acute ischaemia or tumour recurrence and symptoms reversed completely after 1 month and 7 days, respectively. A single photon emission computed tomography scan, performed on the first patient at day 8 post-admission, showed hyperperfusion in the left parieto-occipital region (in the same region as his previous tumour). The clinical histories and outcomes are consistent with the diagnosis of post-cranial irradiation syndrome with migraine-like headaches and prolonged and reversible neurological deficits. Recognition of this disorder is useful in providing reassurance of a favourable prognosis and may also help avoid invasive investigations.