Brain biopsies for neurodegenerative disease in children

The utility of brain biopsy in pediatric cryptogenic neurological disease

OBJECTIVE

The authors' aim was to characterize a single-center experience of brain biopsy in pediatric cryptogenic neurological disease.

METHODS

The authors performed a retrospective review of consecutive brain biopsies at a tertiary pediatric neurosciences unit between 1997 and 2017. Children < 18 years undergoing biopsy for neurological pathology were included. Those with presumed neoplasms and biopsy performed in the context of epilepsy surgery were excluded.

RESULTS

Forty-nine biopsies in 47 patients (25 females, mean age ± SD 9.0 ± 5.3 years) were performed during the study period. The most common presenting symptoms were focal neurological deficit (28.6%) and focal seizure (26.5%). Histopathological, microbiological, and genetic analyses of biopsy material were contributory to the diagnosis in 34 cases (69.4%). Children presenting with focal seizures or with diffuse (> 3 lesions) brain involvement on MRI were more likely to yield a diagnosis at biopsy (OR 3.07 and 2.4, respectively). Twelve patients were immunocompromised and were more likely to yield a diagnosis at biopsy (OR 6.7). Surgery was accompanied by severe complications in 1 patient. The most common final diagnoses were infective (16/49, 32.7%), followed by chronic inflammatory processes (10/49, 20.4%) and occult neoplastic disease (9/49, 18.4%). In 38 cases (77.6%), biopsy was considered to have altered clinical management.

CONCLUSIONS

Brain biopsy for cryptogenic neurological disease in children was contributory to the diagnosis in 69.4% of cases and changed clinical management in 77.6%. Biopsy most commonly revealed underlying infective processes, chronic inflammatory changes, or occult neoplastic disease. Although generally safe, the risk of severe complications may be higher in immunocompromised and myelosuppressed children.

Diagnostic Value and Safety of Brain Biopsy in Patients With Cryptogenic Neurological Disease: A Systematic Review and Meta-analysis of 831 Cases

BACKGROUND

The role of brain biopsy in patients with cryptogenic neurological disease is uncertain.

OBJECTIVE

To determine the risks and benefits of diagnostic brain biopsy for nonneoplastic indications in immunocompetent patients.

METHODS

Appropriate studies were identified by searching electronic databases.

RESULTS

We screened 3645 abstracts and included 20 studies with a total of 831 patients. Indications for biopsy were: (1a) severe neurological disease of unknown etiology in adults (n = 7) and (1b) in children (n = 2); (2) suspected primary angiitis of the central nervous system (PACNS) (n = 3); (3) chronic meningitis of unknown cause (n = 3); (4) atypical dementia (n = 4); and (5) nonneoplastic disease (n = 1). Diagnostic success rates calculated for subgroups were 51.3% (34.5-68.1) for 1a, 53.8% (42.9-64.5) for 1b, 74.7% (64.0-84.1) for 2, 30.3% (17.2-45.4) for 3, and 60.8% (41.2-78.8) for 4. Clinical impact rates were 30.5% (13.6-50.6) for 1a (n = 6), 67.1% (42.8-87.3) for 1b (n = 2), 8.3% (2.3-20.0) for 3 (n = 1), and 14.2% (6.5-24.3) for 4 (n = 2). Lymphoma (n = 32) and Creutzfeldt-Jakob disease (n = 30) were the most common diagnoses on the final histopathology reports of positive brain biopsies in 1a. In 1b, encephalitis (n = 7), PACNS (n = 6), and demyelination (n = 6) were the most common. The odds ratio for achieving a diagnostic biopsy when there was a radiological target was 3.70 (P = .014, 95% confidence interval, 1.31-10.42).

CONCLUSION

Brain biopsy in cryptogenic neurological disease was associated with the highest diagnostic yield in patients with suspected PACNS. The greatest clinical impact was seen in children with cryptogenic neurological disease. The presence of a radiological target was associated with a higher diagnostic yield.

Advances in the diagnosis of leukoencephalopathies

Introduction : Leukoencephalopathies (LEs) are a diverse group of diseases involving cerebral white matter. Some of the disorders may be infectious or immunologically mediated and, therefore, tend to be more amenable to treatment. Most of these disorders have a genetic basis, for which genetic counseling becomes important as currently very few of them have effective therapies. Areas covered : This review calls attention to the diagnostic dilemmas, highlights the diagnostic tests of choice for separating conditions with similar clinical, laboratory or neuroimaging findings, and describes several LEs that have been newly discovered within the last 20 years. Imaging of LEs has progressed rapidly since the introduction of magnetic resonance imaging (MRI) and spectroscopy (MRS), allowing recognition of new diseases, with and without identifiable corresponding biochemical or genetic defects. The distinguishing MRI and MRS features of LEs are described, as well as the resources available for biochemical, CSF and blood sample testing for diagnosis and differentiation from previously known LEs. Expert opinion : Although there is no treatment at present for many of the LEs, their detection as a cause of intellectual and motor disabilities, and as inherited disorders, makes it necessary to accurately categorize them. This knowledge will then allow further elucidation of the etiology, understanding the biological underpinnings, and eventually progress toward rational therapies.

Diagnostic yield of brain biopsies in children presenting to neurology

The role of brain biopsy is well established in patients with neoplastic lesions, with a diagnostic yield approaching 95%. The diagnostic yield of brain biopsy in adults with neurological decline varies from 20% to 43%. Only a few studies have examined the diagnostic yield of brain biopsy in children with idiopathic neurological decline. A retrospective analysis was conducted on all open and closed pediatric brain biopsies performed between January 1988 and May 2003. Biopsies were performed for diagnostic purposes in patients showing a progressively deteriorating neurologic course in whom less-invasive modalities such as neuroimaging, electroencephalography (EEG), and molecular genetic studies were either negative or inconclusive. Immunocompromised patients were included. Patients were excluded if the preoperative diagnosis was a neoplasm or if the patient was undergoing a resection as part of a work-up for intractable epilepsy. Each patient underwent numerous investigations before brain biopsy. The utility of each biopsy was analyzed. Sixty-six children had brain biopsies performed for diagnostic purposes during the study period. Patient ages ranged from 2 months to 16 years and 9 months at the time of biopsy. The diagnostic yield was 48.5% overall, with a yield of 68.8% between 1996 and 2003. Of the total, 26 (39.4%) biopsies were both diagnostic and useful. Patients most frequently presented with seizures (56.1%) and encephalopathy (33%). The most frequently diagnosed disease was vasculitis (18.2%). A total of 71.9% of patients with diagnostic biopsies improved with appropriate treatment. Brain biopsy in children had a diagnostic yield of 48.5% in our series. A specific diagnosis may help in management and outcome, especially with a diagnosis of vasculitis.

Use of computed tomography, magnetic resonance imaging, and localized 1H magnetic resonance spectroscopy in Canavan's disease: a case report

The neuroradiological evaluation of Canavan's disease in a 38-month-old girl is discussed. Computed tomography showed diffuse symmetrical low attenuation values of the subcortical and deep cerebral white matter. Magnetic resonance imaging demonstrated symmetrical diffuse low signal intensity on T1-weighted images and high signal intensity on T2-weighted images. With the use of 1H magnetic resonance spectroscopy, we were able to show elevated levels of N-acetylaspartic acid in the occipital lobe of our patient. The in vivo measurement of N-acetylaspartic acid in the brain by 1H magnetic resonance spectroscopy offers an additional noninvasive diagnostic test for establishing the diagnosis of Canavan's disease. With the increasing availability of magnetic resonance spectroscopy, clinicians may be able to confirm the diagnosis of Canavan's disease immediately after magnetic resonance imaging reveals the typical abnormalities of the white matter.

Comparative neuroimaging with pathologic correlates in Alexander's disease

We describe a case of pathologically confirmed Alexander's disease in which serial cranial ultrasound studies demonstrated unique findings of enlarging subependymal cysts with evolving periventricular hyperechogenicity. Computed tomographic scan of the head showed low attenuation of the periventricular white matter and centrum semiovale. Magnetic resonance imaging (MRI) demonstrated diffuse, confluent high signal predominantly in frontal white matter. These imaging modalities, particularly cranial ultrasound and MRI, may be useful tools in the diagnostic evaluation of children with degenerative neurologic disease, megalencephaly, and suspected Alexander's disease.

Computed tomography in Alexander's disease

Computed tomography demonstrated contrast-enhancing lesions in the periventricular frontal regions, caudate nuclei, and thalami in an infant with Alexander's disease. The distribution of the enhancing lesions corresponded to the areas in which Rosenthal fibers were most prominent. These radiological findings have not been described in other white matter diseases; thus, they may help to distinguish Alexander's disease from Canavan's disease and decrease the necessity for diagnostic brain biopsy.

Computed tomography in the diagnosis of Canavan's disease

Computed tomography (CT scan) demonstrated a symmetrical decrease in white matter attenuation of the cerebral hemispheres of two young children with macrocephaly and normal neurological examination. Subsequent developmental delay led to brain biopsy, which documented Canavan's disease (spongy degeneration of the brain, Van Bogaert-Bertrand type). The CT scans obtained from these patients with proved Canavan's disease appeared to be quite characteristic in differentiating this disorder from Alexander's disease and adrenoleukodystrophy (Schilder's disease). The CT scan may decrease the necessity for diagnostic brain biopsy in these white matter disorders.