Owl's eye in spinal magnetic resonance imaging

Troublemaking Lesions: Spinal Tumor Mimics

There are various mass-like lesions that can mimic true neoplasms in the spine, including inflammatory, infectious, vascular, congenital, and degenerative etiologies. While some lesions have distinctive imaging features that suggest a correct diagnosis, others have overlapping characteristics that do not allow their differentiation based solely on their imaging findings. For entities with nonspecific imaging features, knowledge of the clinical and laboratory information is critical to provide an accurate diagnosis.

A Longitudinally Extensive Spinal Cord Lesion Restricted to Gray Matter in an Adolescent Male

Longitudinally extensive spinal cord lesions (LECL) restricted to gray matter are poorly understood as are their neurodevelopmental repercussions in children. We herein report the critical case of a 13-year-old male presenting with progressive quadriparesis found to have cervical LECL restricted to the anterior horns. Challenged with a rare diagnostic dilemma, the clinical team systematically worked through potential vascular, genetic, infectious, rheumatologic, and paraneoplastic diagnoses before assigning a working diagnosis of acute inflammatory myelopathy. Nuanced consideration of and workup for both potential ischemic causes (arterial dissection, fibrocartilaginous embolism, vascular malformation) and specific inflammatory conditions including Transverse Myelitis, Neuromyelitis Optica Spectrum Disorders (NMOSD), Multiple Sclerosis (MS), Acute Disseminated Encephalomyelitis (ADEM), and Acute Flaccid Myelitis (AFM) is explained in the context of a comprehensive systematic review of the literature on previous reports of gray matter-restricted longitudinally extensive cord lesions in children. Treatment strategy was ultimately based on additional literature review of treatment-refractory acute inflammatory neurological syndromes in children. A combination of high-dose steroids and plasmapheresis was employed with significant improvement in functional outcome, suggesting a potential benefit of combination immune-modulatory treatment in these patients. This case furthermore highlights quality clinical reasoning with respect to the elusive nature of diagnosis, nuances in neuroimaging, and multifocal treatment strategies in pediatric LECL.

Sporadic lower motor neuron disease with a snake eyes appearance on the cervical anterior horns by MRI

OBJECTIVE

Lower motor neuron disease (LMND) is the term generally used to describe diseases in which only lower motor neuron signs are detected. A snake eyes appearance on magnetic resonance imaging (MRI) is associated with a wide spectrum of neurological conditions including LMND. The author reports on three unique LMND patients with upper limb muscle weakness and atrophy who show a snake eyes appearance by MRI.

PATIENTS AND METHODS

The patients were aged 18, 40 and 52 years, respectively, at the onset of the disease and had a longstanding clinical course (more than 10 years for two patients and 8 years for one patient). They were followed up for more than 6 years.

RESULTS

Clinical manifestations were characterized by (1) longstanding slow progression or delayed spontaneous arrest of asymmetric lower motor neuron signs localized exclusively in the upper extremities with unilateral predominance and distal or proximal preponderance; (2) the absence of upper motor neuron signs, bulbar signs, sensory disturbances and respiratory involvement; (3) a snake eyes appearance on the anterior horns of the cervical cord over more than 3 vertebrae by axial T2-weighted MRI and a longitudinal linear-shaped T2-signal hyperintensity by sagittal MRI; (4) neurogenic change with fasciculation and denervation potentials (fibrillation and a positive sharp wave) confined to the affected muscles by needle electromyogram; and (5) normal cerebrospinal fluid and a normal creatine kinase level. These cases did not fall into any existing category of LMND, such as progressive muscular atrophy, flail arm syndrome or Hirayama disease.

CONCLUSIONS

These patients should be classified as sporadic LMND with snake eyes on MRI with a relatively benign prognosis.

Monomelic amyotrophy: clinical profile and natural history of 279 cases seen over 35 years (1976-2010)

Our objective was to study the clinical characteristics and natural history of monomelic amyotrophy (MMA). We used a retrospective study of 279 patients diagnosed to have either upper (Hirayama disease) or lower limb MMA. Results showed that brachial MMA (BMMA) occurred in 224 patients (male:female, 9:1). Mean age of onset was 19.5 ± 4.18 years. Progression occurred over less than five years in the majority (95.9%) of patients. Duration at the last follow-up was: up to five years in 61.4%, 5-10 in 21.3%, 10-15 in 7.2%, > 15 years in 10.1%. MRI showed asymmetrical lower cervical cord atrophy in 44.6% of patients. Crural MMA (CMMA) occurred in 55 patients (male:female, 13:1). Mean age of onset was 21.38 ± 5.3 years. Similar to BMMA, most cases (65.5%) had onset between 15 and 25 years of age. Total duration of illness at the last follow-up was up to five years in 52.7%, 10 and beyond in 47.3%. In conclusion, a large cohort of patients with monomelic amyotrophy seen over 35 years (1976-2010) is described. Study data support the clinical findings and its natural history with long term follow-up, and the findings emphasize that monomelic amyotrophy is a 'benign' condition with a self-limiting course.

The challenge of diagnosing the acute nontraumatic tetraplegia of a healthy young woman

Acute nontraumatic myelopathies include vascular etiologies most commonly caused by atherosclerotic vascular disease. Other causes that have been reported to occur with varying frequencies include thrombosis, embolism of thrombi and tumor, arteritis, hypotension, dissecting aortic aneurysm, sickle cell disease, intervertebral disk herniation, vertebral body subluxation and iatrogenic causes, usually angiography or surgery. In case of acutely progressing spinal cord syndromes, the diagnosis often given is of transverse myelitis or unknown cause of infarction. Fibrocartilaginous embolism (FCE) is possible cause of spinal ischemia due to embolization of nucleus pulposus fragments through retrograde spinal artery flow. A young woman after intensive exercise developed profound weakness of her upper extremities, progressing to flaccid quadriplegia with sensory level from C3 dermatome. Magnetic resonance imaging (MRI) showed linear hyperintense intramedullary lesion from C2 to Th2 confined to anterior horn area, with typical"owl's eye" appearance. Although exact mechanism of patient's neurological syndrome remains undetermined, we suspected a cord infarction due to FCE related to her vigorous physical exercise.