Long-term MR imaging course of neurodegenerative Langerhans cell histiocytosis

A multidisciplinary non-invasive approach to monitor response to intravenous immunoglobulin treatment in neurodegenerative Langerhans cell histiocytosis: a real-world study

Aims

Early detection and treatment of neurodegenerative Langerhans cell histiocytosis (ND-LCH) have been suggested to prevent neurodegenerative progression. The aim of the study is to validate a standardized multidisciplinary diagnostic work-up to monitor the intravenous immunoglobulins (IVIG) treatment response and the natural course of the disease in untreated patients.

Methods

Patients with abnormal somatosensory evoked potentials (SEPs) received monthly 0.5 g/kg IVIG. The diagnostic protocol included structural 3T MRI, neurological examination, brainstem auditory evoked potentials (BAEPs) and SEPs.

Results

Twenty-two patients were followed for 5.2 years (median) from the first MRI evidence of ND-LCH. Eleven patients received IVIG for 1.7 years (median). At treatment start neurological examination was abnormal in 10 patients, of whom two had severe clinical impairment and four had abnormal BAEPs. At last follow-up, 1/11 remained stable and 7/11 improved, while worsening of neurological or neurophysiological findings, or both, occurred in 3/11. Risk factors for worsening were a severe clinical or MRI ND-LCH at treatment initiation and prolonged exposure to LCH. Of the 11 untreated patients, none improved and three worsened.

Conclusions

Using a standardized diagnostic protocol, we demonstrated that IVIG treatment can lead to clinical stabilization or improvement in all pauci-symptomatic patients with an MRI grading of less than 4.

Mechanism of neurodegeneration mediated by clonal inflammatory microglia

Langerhans cell Histiocytosis (LCH) and Erdheim-Chester disease (ECD) are clonal myeloid disorders, associated with MAP-Kinase activating mutations and an increased risk of neurodegeneration. Surprisingly, we found pervasive PU.1+ microglia mutant clones across the brain of LCH and ECD patients with and without neurological symptoms, associated with microgliosis, reactive astrocytosis, and neuronal loss. The disease predominated in the grey nuclei of the rhombencephalon, a topography attributable to a local proliferative advantage of mutant microglia. Presence of clinical symptoms was associated with a longer evolution of the disease and a larger size of PU.1+ clones (p= 0.0003). Genetic lineage tracing of PU.1+ clones suggest a resident macrophage lineage or a bone marrow precursor origin depending on patients. Finally, a CSF1R-inhibitor depleted mutant microglia and limited neuronal loss in mice suggesting an alternative to MAPK inhibitors. These studies characterize a progressive neurodegenerative disease, caused by clonal proliferation of inflammatory microglia (CPIM), with a decade(s)-long preclinical stage of incipient disease that represent a therapeutic window for prevention of neuronal death.

[Central nervous system disorders secondary to histiocytoses: neurodegeneration with potential for improvement]

Histiocytoses, including Langerhans cell histiocytosis (LCH) and Erdheim-Chester disease (ECD), are inflammatory myeloid tumors in which monocyte lineage cells aggregate in various organs, causing tissue damage. Most of these tumors harbor oncogenic mutations in mitogen-activated protein kinase (MAPK) pathway genes, typified by BRAFV600E. Some patients with LCH develop bilateral symmetrical cerebellar lesions and brain atrophy several years after diagnosis when the initial symptoms disappear, leading to cerebellar ataxia and higher cerebral dysfunction. A similar neurological disorder has also been reported in ECD. This neurological disorder can be improved with MAPK inhibitors. When patients with this neurological disorder are identified among neurodegeneration of unknown etiology or histiocytosis patients and treated early with MAPK inhibitors, the disorder can be reversible.

Cerebellar peduncle damage in Langerhans cell histiocytosis-associated neurodegenerative disease revealed by diffusion tensor imaging

PURPOSE

To confirm the hypothesis that brain white matter damage is involved in the pathogenesis and disease progression of Langerhans cell histiocytosis (LCH)-associated neurodegenerative disease (ND), we aimed to analyze pediatric patients with LCH using diffusion tensor imaging (DTI).

METHODS

We enrolled 33 patients with LCH and obtained 33 DTI datasets. Using DTI-based tractography, fractional anisotropy (FA), apparent diffusion coefficient (ADC), axial diffusivity (AD), and radial diffusivity (RD) were measured in the cerebral and cerebellar white matter tracts. The participants were divided into three groups-non-ND, ND without clinical symptoms (r-ND), and ND with clinical symptoms (c-ND)-according to their clinical status during the examination with DTI. We compared the DTI parameters in white matter tracts were compared among the three groups.

RESULTS

In the order of non-ND, r-ND, and c-ND groups, the FA in superior cerebellar peduncle (SCP) and middle cerebellar peduncle (MCP) significantly decreased, the ADC, AD, and RD of MCP, and the RD of SCP were significantly elevated (FA-SCP; p < 0.001, FA-MCP; p = 0.026, ADC-MCP; p < 0.001, AD-MCP; p = 0.002, RD-MCP; p = 0.003, and RD-SCP; p = 0.018). Furthermore, in the simple linear regression analysis, the FA, ADC, AD, and RD values in the MCP and the FA value in the SCP were significantly influenced by the presence of neurological symptoms and ND findings on MRI (all p < 0.001).

CONCLUSION

In LCH-ND, we identified microstructural damage in the SCP and MCP. DTI parameters in these tracts may help monitor LCH-ND; therefore, future studies are required to validate these results in a large cohort.

Neuroimaging manifestations of paediatric histiocytoses

Histiocytoses are rare multi-system disorders marked by abnormal histiocyte cell proliferation, affecting children with diverse clinical presentations. Classified into five groups in 2016, including Langerhans-related (L), cutaneous (C), malignant (M), Rosai-Dorfman disease (R) and haemophagocytic lymphohistiocytosis (H), newer entities such as ALK-positive histiocytosis have also emerged, heralding the era of molecular (sub)classification. Common entities include Langerhans cell histiocytosis (LCH), Erdheim-Chester disease (ECD), Rosai-Dorfman disease (RDD) and haemophagocytic lymphohistiocytosis (HLH). This pictorial essay aids radiologists in recognising and differentiating paediatric histiocytoses based on unique neuroimaging features.

Erdheim-Chester Disease

Erdheim-Chester disease is a rare non-Langerhans cell histiocytosis. The disease is widely variable in its severity, ranging from incidental findings in asymptomatic patients to a fatal multisystem illness. CNS involvement occurs in up to one-half of patients, most often leading to diabetes insipidus and cerebellar dysfunction. Imaging findings in neurologic Erdheim-Chester disease are often nonspecific, and the disease is commonly mistaken for close mimickers. Nevertheless, there are many imaging manifestations of Erdheim-Chester disease that are highly suggestive of the disease, which an astute radiologist could use to accurately indicate this diagnosis. This article discusses the imaging appearance, histologic features, clinical manifestations, and management of Erdheim-Chester disease.

Neuroimaging in Pediatric Patients with Juvenile Xanthogranuloma of the CNS

BACKGROUND AND PURPOSE

Juvenile xanthogranuloma is a rare clonal, myeloid, neoplastic disorder. Typically, juvenile xanthogranuloma is a self-limited disorder of infancy, often presenting as a solitary red-brown or yellow skin papule/nodule. A small subset of patients present with extracutaneous, systemic juvenile xanthogranuloma, which may include the CNS. The goal of this retrospective study was to evaluate and categorize the neuroimaging findings in a representative cohort of pediatric patients with CNS juvenile xanthogranuloma.

MATERIALS AND METHODS

The brain and/or spine MR imaging data of 14 pediatric patients with pathology-proven juvenile xanthogranuloma were categorized and evaluated for the location; the signal intensity of xanthogranulomas on T1WI, T2WI, DWI, and a matching ADC map for the pattern and degree of contrast enhancement; and the presence of perilesional edema, cysts, or necrosis.

RESULTS

Fourteen pediatric patients (8 girls, 6 boys; mean age, 84 months) were included in the study. Patients presented with a wide variety of different symptoms, including headache, seizure, ataxia, strabismus, hearing loss, facial paresis, and diabetes insipidus. Juvenile xanthogranuloma lesions were identified in a number of different sites, including supra- and infratentorial as well as intracranial and spinal leptomeningeal. Five patients were categorized into the neuroradiologic pattern unifocal CNS juvenile xanthogranuloma; 8, into multifocal CNS juvenile xanthogranuloma; and 1, into multifocal CNS juvenile xanthogranuloma with intracranial and spinal leptomeningeal disease. In most cases, xanthogranulomas were small-to-medium intra-axial masses with isointense signal on T1WI (compared with cortical GM), iso- or hyperintense signal on T2WI, had restricted diffusion and perilesional edema. Almost all xanthogranulomas showed avid contrast enhancement. However, we also identified less common patterns with large lesions, nonenhancing lesions, or leptomeningeal disease. Four cases had an additional CT available. On CT, all xanthogranulomas were homogeneously hyperdense (solid component) without evident calcifications.

CONCLUSIONS

CNS juvenile xanthogranuloma may demonstrate heterogeneous neuroimaging appearances potentially mimicking other diseases, such as primary brain neoplasms, metastatic disease, lymphoma and leukemia, other histiocytic disorders, infections, or granulomatous diseases.

Neuroimaging in cerebellar ataxia in childhood: A review

Ataxia is one of the most common pediatric movement disorders and can be caused by a large number of congenital and acquired diseases affecting the cerebellum or the vestibular or sensory system. It is mainly characterized by gait abnormalities, dysmetria, intention tremor, dysdiadochokinesia, dysarthria, and nystagmus. In young children, ataxia may manifest as the inability or refusal to walk. The diagnostic approach begins with a careful clinical history including the temporal evolution of ataxia and the inquiry of additional symptoms, is followed by a meticulous physical examination, and, depending on the results, is complemented by laboratory assays, electroencephalography, nerve conduction velocity, lumbar puncture, toxicology screening, genetic testing, and neuroimaging. Neuroimaging plays a pivotal role in either providing the final diagnosis, narrowing the differential diagnosis, or planning targeted further workup. In this review, we will focus on the most common form of ataxia in childhood, cerebellar ataxia (CA). We will discuss and summarize the neuroimaging findings of either the most common or the most important causes of CA in childhood or present causes of pediatric CA with pathognomonic findings on MRI. The various pediatric CAs will be categorized and presented according to (a) the cause of ataxia (acquired/disruptive vs. inherited/genetic) and (b) the temporal evolution of symptoms (acute/subacute, chronic, progressive, nonprogressive, and recurrent). In addition, several illustrative cases with their key imaging findings will be presented.

Waxing and Waning Neuroimaging Abnormalities in Langerhans Cell Histiocytosis

Langerhans cell histiocytosis (LCH) is a rare disease in adults characterized by proliferation of CD1a+/CD207+ and S100 myeloid dendritic cells, forming granulomas.1 An inflammatory exudate is often found with “bean-shaped” nucleated histiocytes. We report a patient with multisystem (liver, lung and brain) LCH in whom neuroimaging abnormalities accumulated and partially regressed prior to definitive treatment.

Langerhans Cell Histiocytosis of the Orbit: Spectrum of Clinical and Imaging Findings

OBJECTIVE

To evaluate the clinical and imaging characteristics of orbital lesions of pediatric Langerhans cell histiocytosis (LCH).

STUDY DESIGN

A retrospective analysis of clinical data and central review of magnetic resonance imaging scans in patients with LCH, enrolled into one of the consecutive international trials LCH I-III, or submitted for a second opinion between 1994 and 2015.

RESULTS

Data from 31 children (34 involved orbits) were analyzed. Orbital LCH was the only disease manifestation in 15, part of a multifocal skeletal in 5, or a multisystem LCH in 11 patients. Orbital LCH was part of the initial disease presentation in 23 or developed at relapse in 8 cases. Orbital involvement was unilateral in 28 and bilateral in 3 patients (34 affected orbits). Proptosis was present in 9 patients. Frontal and zygomatic bone were most commonly affected. All orbital lesions were extraconal. Associated extraorbital imaging findings were dural tail sign in 19, neurodegeneration in 8, and hypothalamic-pituitary mass in 3 patients. Sixteen patients (52%) had at least 1 documented disease relapse. Permanent consequences were prominent proptosis in 1, diabetes insipidus in 8, growth hormone deficiency in 2, radiologic neurodegeneration in 8, and clinical neurodegeneration in 3 patients.

CONCLUSIONS

Predominantly unilateral orbital LCH can be the only disease manifestation or part of a disseminated disease. Orbital lesions in LCH are exclusively extraconal, typically located at the roof and the lateral wall of the orbit. The optimal treatment approach of unifocal LCH of the orbit remains controversial and warrants a prospective evaluation.

MRI features of intra-axial histiocytic brain mass lesions

AIM

To describe MRI features, including diffusion-weighted imaging (DWI), magnetic resonance spectroscopy (MRS), and perfusion-weighted imaging (PWI), of intra-axial tumour-like presentations of four different subtypes of histiocytosis.

MATERIAL AND METHODS

The brain MRI findings of 23 patients with histologically proven histiocytosis were reviewed retrospectively (11 Langerhans cell histiocytosis [LCH], eight Erdheim-Chester disease [ECD], one overlap form LCH/ECD, two Rosai-Dorfman disease [RDD], and one haemophagocytic lymphohistiocytosis [HLH]) with single or multiple enhancing intraparenchymal brain lesions.

RESULTS

Histiocytic brain mass lesions show some similar MRI features including Supra and/or infratentorial and/or paraventricular subcortical well-delineated masses, linear ependymal enhancement along the ventricles and brain stem lesions. Masses always present with mixed hyper- and hypointense signal on T2-weighted imaging (WI). Their enhancement is often homogeneous. Apparent diffusion coefficient (ADC) values are often normal or elevated.

CONCLUSION

The presence of multiple periventricular and subcortical enhancing lesions with mixed signal intensity on T2WI and normal or high ADC values should lead radiologists to consider the diagnosis of histiocytic lesions and search for associated systemic lesions.

Osteopontin is highly secreted in the cerebrospinal fluid of patient with posterior pituitary involvement in Langerhans cell histiocytosis

BACKGROUND

Langerhans cell histiocytosis (LCH) is a rare disease caused by clonal proliferation of CD1a⁺ CD207⁺ cells. Distinguishing pituitary involvement was essential in stratification and treatment of patients with LCH. The diagnosis of pituitary involvement is mainly dependent on hormone abnormalities in the anterior pituitary and magnetic resonance imaging (MRI) scanning in posterior pituitary. Diabetes insipidus (DI) is a serious sequelae and often occurred with pituitary involvement. It is reported that osteopontin (OPN) is highly secreted in the cerebrospinal fluid (CSF) of patients with neurodegenerative diseases in LCH (LCH-ND). However, patients with posterior pituitary involvement account for a larger portion in our hospital. Whether the OPN level could be an auxiliary diagnostic marker for the posterior pituitary involvement or not is still unknown.

METHODS

In our study, we collected CSF samples of 57 children with LCH. The secreted OPN (sOPN) levels in CSF were measured through enzyme-linked immunosorbent assay (ELISA).

RESULTS

After the retrospective analysis of 57 patients with LCH, we found that the sOPN levels in CSF of children with posterior pituitary involvement were significantly higher than that of other groups. After the Pearson Chi-Square test, Fisher's exact test and ROC analysis, we found that the sOPN levels were significantly correlated with posterior pituitary involvement. The cut-off value is 214.14 ng/mL.

CONCLUSION

The sOPN levels were elevated in CSF of LCH children with posterior pituitary involvement. Analysis of the sOPN level may provide more accurate auxiliary diagnostic techniques for the clinic.

The spectrum of immune-mediated and inflammatory lesions of the brainstem: Clues to diagnosis

The presentation of a patient with brainstem symptoms and signs invokes a number of common and less common differential diagnoses, and accurate diagnosis can be challenging. We review the major immune-mediated and inflammatory syndromes that can affect the brainstem including multiple sclerosis, neuromyelitis optica spectrum disorder, neuro-Behçet disease, chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids, neurosarcoidosis, Susac syndrome, and the histiocytic disorders. We focus on clinical features and MRI clues that help to distinguish among the different brainstem conditions. Accurate diagnosis is important to guide appropriate treatment and limit neurologic disability.

Neuroimaging features of CNS histiocytosis syndromes

Histiocytosis syndromes (HS) are group of heterogeneous disorders characterized by abnormal accumulation and infiltration of histiocytes, cells derived from hematopoietic cells of monocyte/macrophage lineage. Overall these disorders are rare. When they do occur they involve many organ systems including the central nervous system (CNS). While imaging findings can provide important clues, diagnosis of this disorder is challenging and definitive diagnosis often necessitates pathologic examination. In this review, we describe imaging features of HS involving the CNS, with the aim to increase our understanding of these disorders. The entities discussed in this review will include: Langerhans cell histiocytosis (LCH), Rosai-Dorfman Disease (RDD), Erdheim Chester Disease (ECD), hemophagocytic lymphohistiocytosis (HLH), and crystal-storing histiocytosis (CSH).

Visible T1-hyperintensity of the dentate nucleus after multiple administrations of macrocyclic gadolinium-based contrast agents: yes or no?

OBJECTIVES

To investigate the appearance of visible dentate nucleus (DN) T1-hyperintensity and quantify changes in DN/pons (DN/P) signal intensity (SI) ratio in MS patients after the exclusive administration of macrocyclic GBCAs.

MATERIALS AND METHODS

One hundred forty-nine patients with confirmed MS were evaluated. Patients received at least two administrations of gadobutrol (n = 63), gadoterate (n = 57), or both (n = 29). Two experienced neuroradiologists in consensus evaluated unenhanced T1-weighted MR images from all examinations in each patient for evidence of visible DN hyperintensity. Thereafter, SI measurements were made in the left and right DN and pons on unenhanced T1-weighted images from the first and last scans. A two-sample t test compared the DN/P SI ratios for patients with and without visible T1-hyperintensity.

RESULTS

Visible T1-hyperintensity was observed in 42/149 (28.2%) patients (19 after gadobutrol only, 15 after gadoterate only, 8 after both), typically at the 4th or 5th follow-up exam at 3-4 years after the initial examination. Significant increases in DN/P SI ratio from first to last examination were determined for patients with visible T1-hyperintensity (0.998 ± 0.002 to 1.153 ± 0.016, p < 0.0001 for gadobutrol; 1.003 ± 0.004 to 1.110 ± 0.014, p < 0.0001 for gadoterate; 1.004 ± 0.011 to 1.163 ± 0.032, p = 0.0004 for both) but not for patients without visible T1-hyperintensity (p > 0.05; all groups).

CONCLUSION

Multiple injections of gadobutrol and/or gadoterate can lead to visible and quantifiable increases in DN/P SI ratio in some patients with MS.

[Gadolinium deposition-"gadolinium deposition disease"]

Gadolinium (Gd)-based contrast agents have been routinely used worldwide in diagnostic MRI since 1988. All routinely applied contrast agents for clinical use were considered extremely safe with regard to tolerance, adverse effects and diagnostic efficacy and when used at Food and Drug Administration-approved doses. With the identification of Gd-associated disorders, namely nephrogenic systemic fibrosis and adverse reactions, and in the longer term Gd-retention in the brain, this view changed and led to the withdrawal or restriction of approval of linear Gd chelates in Europe. Even though Gd deposition in different human body areas was described very early, recently published literature of intracerebral accumulation of contrast agents as well as deposition in bone have created surprising attention. Not only was the fact of Gd deposition in the body well known for many years, but there is currently no clinical evidence of patient symptoms and no resulting health issues of patients have been observed yet. The expression "gadolinium deposition disease" has been termed by active patient advocacy groups with an online presence with reports of individual members stating a broad spectrum of disorders yielding a large symptom complex after administration of Gd-based contrast agents without evidence of any pre-existing or otherwise underlying disease process which could explain the mentioned disorder.

Rituximab therapy for patients with Langerhans cell histiocytosis-associated neurologic dysfunction

OBJECTIVE

Since patients with langerhans cell histiocytosis and neurologic dysfunction (LCH-ND) often have incomplete treatment responses we sought a new treatment regimen. Because of clinical benefit from rituximab in multiple sclerosis patients with neurodegeneration, we evaluated its use in patients with LCH-ND.

PARTICIPANTS

Eight LCH-ND patients who had failed prior therapies.

METHODS

Charts of the 8 patients treated with rituximab were reviewed. Signs/symptoms and MRI responses were assessed.

RESULTS

Seven of eight patients experienced some clinical improvement: gait abnormalities and tremors in four children, proprioceptive deficits in 2, and dysarthria/dysphagia in 2. Five of eight patients demonstrated improvement in intellectual/behavioral/psychological symptoms.

CONCLUSION

These findings suggest that prospective studies are warranted to define safety and efficacy of rituximab for patients with LCH-ND.

Effects of serial macrocyclic-based contrast materials gadoterate meglumine and gadobutrol administrations on gadolinium-related dentate nuclei signal increases in unenhanced T1-weighted brain: a retrospective study in 158 multiple sclerosis (MS) patients

PURPOSE

To perform T1 signal intensity (SI) measurements in the dentate nuclei of adult patients with confirmed multiple sclerosis (MS) after serial administrations of the macrocyclic gadolinium-based contrast agents (GBCAs), gadoterate meglumine and gadobutrol.

MATERIALS AND METHODS

This retrospective study was approved by the institutional review board and informed consent was waived. A review of our PACS database for the period from March 1, 2007 to July 31, 2016 revealed 158 confirmed MS patients who received exclusively either gadoterate meglumine (n = 81) or gadobutrol (n = 77) for diagnosis and follow-up. SI measurements on unenhanced T1-weighted images were performed on all scans of all patients and at regions of interest (ROIs) positioned on the dentate nucleus (DN) and pons. The dentate nucleus-to-pons (DNP) T1-SI ratio was subsequently calculated. Unpaired T test and regression analysis were used to evaluate statistical differences.

RESULTS

An increase in DNP was noted between the first and last MR examinations for both gadoterate meglumine (0.0032 ± 0.0216) and gadobutrol (0.0019 ± 0.0346). Although the differences were not statistically significant based across the entire patient population, visible T1 hyperintensity in the DN was noted in approximately one-third of all patients in each group that received at least five administrations of either GBCA.

CONCLUSIONS

SI increases on unenhanced T1-weighted images possibly indicative of gadolinium retention occur after serial administrations of the macrocyclic GBCAs, gadoterate meglumine and gadobutrol.

Cerebellar Disease Mimicking Cerebrotendinous Xanthomatosis: Langerhans Cell Histiocytosis

BACKGROUND

This report highlights the differential diagnosis of predominant cerebellar white matter abnormalities with dentate nuclei involvement.

PATIENT DESCRIPTION

We describe two individuals with Langerhans cell histiocytosis in whom the diagnosis of cerebrotendinous xanthomatosis was initially considered. The clinical picture consisted of a progressive cerebellar syndrome with typical magnetic resonance imaging abnormalities. In both individuals, the cerebellar syndrome preceded the diagnosis of Langerhans cell histiocytosis.

CONCLUSIONS

The magnetic resonance imaging abnormalities and neurological features in patients with Langerhans cell histiocytosis can be strikingly similar to those with cerebrotendinous xanthomatosis. In cerebrotendinous xanthomatosis, the cerebellar symptoms and cerebellar white matter abnormalities are usually seen in adult patients. In a pediatric patient with a cerebellar syndrome, showing these cerebellar white matter abnormalities a diagnosis of Langerhans cell histiocytosis is more likely.

T1 Signal Measurements in Pediatric Brain: Findings after Multiple Exposures to Gadobenate Dimeglumine for Imaging of Nonneurologic Disease

BACKGROUND AND PURPOSE

Signal intensity increases possibly suggestive of gadolinium retention have recently been reported on unenhanced T1-weighted images of the pediatric brain following multiple exposures to gadolinium-based MR contrast agents. Our aim was to determine whether T1 signal changes suggestive of gadolinium deposition occur in the brains of pediatric nonneurologic patients after multiple exposures to gadobenate dimeglumine.

MATERIALS AND METHODS

Thirty-four nonneurologic patients (group 1; 17 males/17 females; mean age, 7.18 years) who received between 5 and 15 injections (mean, 7.8 injections) of 0.05 mmol/kg of gadobenate during a mean of 2.24 years were compared with 24 control patients (group 2; 16 males/8 females; mean age, 8.78 years) who had never received gadolinium-based contrast agents. Exposure to gadobenate was for diagnosis and therapy monitoring. Five blinded readers independently determined the signal intensity at ROIs in the dentate nucleus, globus pallidus, pons, and thalamus on unenhanced T1-weighted spin-echo images from both groups. Unpaired t tests were used to compare signal-intensity values and dentate nucleus-pons and globus pallidus-thalamus signal-intensity ratios between groups 1 and 2.

RESULTS

Mean signal-intensity values in the dentate nucleus, globus pallidus, pons, and thalamus of gadobenate-exposed patients ranged from 366.4 to 389.2, 360.5 to 392.9, 370.5 to 374.9, and 356.9 to 371.0, respectively. Corresponding values in gadolinium-based contrast agent-naïve subjects were not significantly different (P > .05). Similarly, no significant differences were noted by any reader for comparisons of the dentate nucleus-pons signal-intensity ratios. One reader noted a difference in the mean globus pallidus-thalamus signal-intensity ratios (1.06 ± 0.006 versus 1.02 ± 0.009, P = .002), but this reflected nonsignificantly higher T1 signal in the thalamus of control subjects. The number of exposures and the interval between the first and last exposures did not influence signal-intensity values.

CONCLUSIONS

Signal-intensity increases potentially indicative of gadolinium deposition are not seen in pediatric nonneurologic patients after multiple exposures to low-dose gadobenate.

Diffuse Encephalopathy Associated with Isolated Cerebral Langerhans Cell Histiocytosis

BACKGROUND

Langerhans cell histiocytosis is a rare disease of the monocyte-macrophage system. Abnormalities of the hypothalamic-pituitary region are common in individuals with central nervous system involvement.

PATIENT DESCRIPTION

This six-year-old boy developed rapidly progressive aggressive behavior, central diabetes insipidus, and repeated complex partial seizures. Magnetic resonance imaging revealed a diffuse leukoencephalopathy-like pattern and numerous infratentorial and supratentorial granulomatous nodules in the brain parenchyma along with infundibular and hypothalamic mass lesions. Stereotactic serial biopsies enabled histopathologic and immunohistochemical diagnosis of Langerhans cell histiocytosis.

CONCLUSIONS

Similar MRI findings have rarely been described in the literature. These findings represent part of the broad neuroradiological spectrum of Langerhans cell histiocytosis of the nervous system in children.

Central nervous system imaging in childhood Langerhans cell histiocytosis - a reference center analysis

BACKGROUND

The aim of our study was (1) to describe central nervous system (CNS) manifestations in children with Langerhans cell histiocytosis (LCH) based on images sent to a reference center and meeting minimum requirements and (2) to assess the inter-rater agreement of CNS-MRI results, which represents the overall reproducibility of this investigation.

METHODS

We retrospectively reviewed brain MRI examinations in children with LCH, for which MRI minimum requirements were met. Abnormalities were rated by two experienced neuroradiologists, and the inter-rater agreement was assessed.

RESULTS

Out of a total of 94 imaging studies, only 31 MRIs met the minimum criteria, which included T2w, FLAIR, T1w images before/after contrast in at least two different section planes, and thin post contrast sagittal slices T1w through the sella. The most common changes were osseous abnormalities, followed by solid enlargement of the pineal gland, thickened enhancing stalk and signal changes of the dentate nucleus. Whereas inter-rater agreement in assessing most of the CNS lesions was relatively high (κ > 0.61), the application of minimum criteria often did not allow to evaluate the posterior pituitary.

CONCLUSIONS

The diversity of radiological protocols from different institutions leads to difficulties in the diagnosis of CNS abnormalities in children with LCH. Although the inter-rater agreement between neuroradiologists was high, not all the LCH manifestations could be completely ruled out when using the minimum criteria. Brain MRIs should therefore follow LCH guideline protocols and include T1 pre-gadolinium sagittal images, and be centrally reviewed in order to improve the comparison of clinical trials.

Clinical Characteristics and Treatment of Langerhans Cell Histiocytosis

Langerhans cell histiocytosis (LCH) is a disease caused by clonal proliferation of CD1a+/CD207+ cells that is characterized by a spectrum of varying degrees of organ involvement and dysfunction. Treatment of LCH is risk adapted; patients with single lesions may respond well to local treatment, whereas patients with multi-system disease and risk-organ involvement require more intensive therapy. Although survival for patients without organ dysfunction is excellent, mortality rates for patients with organ dysfunction may reach 30% to 40%. For patients with low-risk disease, although cure is almost universal, disease reactivation rates are in excess of 30%.

Early Diagnosis and Monitoring of Neurodegenerative Langerhans Cell Histiocytosis

Background

Neurodegenerative Langerhans Cell Histiocytosis (ND-LCH) is a rare, unpredictable consequence that may devastate the quality of life of patients cured from LCH. We prospectively applied a multidisciplinary diagnostic work-up to early identify and follow-up patients with ND-LCH, with the ultimate goal of better determining the appropriate time for starting therapy.

Methods

We studied 27 children and young adults with either ND-LCH verified by structural magnetic resonance imaging (MRI) (group 1) or specific risk factors for (diabetes insipidus, craniofacial bone lesions), but no evidence of, neurodegenerative MRI changes (group 2). All patients underwent clinical, neurophysiological and MRI studies.

Results

Seventeen patients had MRI alterations typical for ND-LCH. Nine showed neurological impairment but only three were symptomatic; 11 had abnormal somatosensory evoked potentials (SEPs), and five had abnormal brainstem auditory evoked potentials (BAEPs). MR spectroscopy (MRS) showed reduced cerebellar NAA/Cr ratio in nine patients. SEPs showed sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for predicting ND-LCH of 70.6% (95%CI, 44.0%-89.7%), 100% (69.2%-100%), 100% (73.5%-100%), and 66.7% (38.4%-88.2%), respectively. Repeated investigations in group 1 revealed increasingly abnormal EP parameters, or neurological examination, or both, in nine of fifteen patients while MRI remained unchanged in all but one patient.

Conclusion

A targeted MRI study should be performed in all patients with risk factors for ND-LCH for early identification of demyelination. The combined use of SEPs and careful neurological evaluation may represent a valuable, low-cost, well-tolerated and easily available methodology to monitor patients from pre-symptomatic to symptomatic stages. We suggest a multidisciplinary protocol including clinical, MRS, and neurophysiological investigations to identify a population target for future therapeutic trials.

Histiocytosis: a review focusing on neuroimaging findings

OBJECTIVE

Histiocytosis is a systemic disease that usually affects the central nervous system. The aim of this study is to discuss the neuroimaging characteristics of Langerhans cell histiocytosis (LCH), the most common of these diseases; and the non-Langerhans cells histiocytosis (NLCH), which includes entities such as hemophagocytic syndrome, Erdheim-Chester and Rosai-Dorfman diseases.

METHOD

Literature review and illustrative cases with pathologic confirmation.

RESULTS

In LCH, the most common findings are 1) osseous lesions in the craniofacial bones and/or skull base; 2) intracranial, extra-axial changes; 3) intra-axial parenchymal changes (white and gray matter); 4) atrophy. Among the NLCH, diagnosis usually requires correlation with clinical and laboratory criteria. The spectrum of presentation includes intraparenchymal involvement, meningeal lesions, orbits and paranasal sinus involvement.

CONCLUSION

It is important the recognition of the most common imaging patterns, in order to include LCH and NLCH in the differential diagnosis, whenever pertinent.

Neuroimaging of Langerhans cell histiocytosis: a radiological review

The neuroimaging of Langerhans cell histiocytosis (LCH), in most of the cases, is nonspecific and can vary depending on the location, especially as shown on magnetic resonance imaging (MRI). In the absence of a clinical history of LCH, isolated central nervous system (CNS) lesion presents a diagnostic challenge. LCH should be considered in the differential diagnosis of craniofacial tumors and neurodegenerative (ND) lesions of the brain. MRI is the modality of choice for investigating the CNS-LCH. Long-term follow-up with MRI is indicated in patients with ND-LCH. This retrospective study provides a comprehensive description of the spectrum of neuroimaging findings in patients with LCH, the underlying neuropathology, and follow-up study of the disease.

Recent advances in Langerhans cell histiocytosis

The purpose of this review is to provide an updated overview of the pathogenesis and treatment of Langerhans cell histiocytosis (LCH). The pathogenesis of LCH remains obscure and the optimal treatment for LCH has not been established, although incremental progress has been made. Proinflammatory cytokines and chemokines are known to play a role in LCH, which suggests that LCH is an immune disorder. However, the oncogenic BRAF mutation is also detected in more than half of LCH patients, which suggests that LCH is a neoplastic disorder. Remaining major issues in the treatment of LCH are how to rescue patients who have risk-organ involvement but do not respond to first-line therapy, the optimal treatment for the orphan disease of multifocal adult LCH, and how to reduce and treat central nervous system-related consequences, such as central diabetes insipidus and neurodegeneration. More research is needed to better understand the pathogenesis of this disease and to resolve the treatment issues.

[Neuroimaging of Langerhans cell histiocytosis in the central nervous system of children]

Langerhans cell histiocytosis (LCH) is a rare disease characterized by the accumulation within tissues of anomalous dendritic cells similar to Langerhans cells. The clinical presentation varies, ranging from the appearance of a single bone lesion to multisystemic involvement. Central nervous system (CNS) involvement, manifesting as diabetes insipidus secondary to pituitary involvement, has been known since the original description of the disease. Two types of CNS lesions are currently differentiated. The first, pseudotumoral lesions with infiltration by Langerhans cells, most commonly manifests as pituitary infiltration. The second, described more recently, consists of neurodegenerative lesions of the CNS associated with neurologic deterioration. This second type of lesion constitutes a complication of the disease; however, there is no consensus about the cause of this complication. Our objective was to describe the radiologic manifestations of LCH in the CNS in pediatric patients.

Long-term outcome of hypothalamic pituitary tumors in Langerhans cell histiocytosis

BACKGROUND

Hypothalamic-pituitary (HP) disease is the most common CNS manifestation of Langerhans cell histiocytosis (LCH) frequently leading to diabetes insipidus (DI) and anterior pituitary hormone deficiencies (APD). On MRI, loss of the normal posterior pituitary signal and thickening of the pituitary stalk have been described, as well as neurodegenerative signal changes associated with neuropsychological disabilities in some patients. The influence of therapy on the long-term course of HP tumors and neurodegeneration (ND) is not well-understood.

PROCEDURE

In this retrospective survey we focused on patients with LCH and HP disease with clinical and MRI data available at diagnosis of HP disease and at least three follow up investigations. We collected clinical and MRI follow-up information for central review and analysis.

RESULTS

We identified 22 patients with HP tumors (HPT) registered at the LCH study center. Many different treatment regimens were applied for variable periods, with more than one regimen in most patients. Regression of the tumor was seen in the majority, but all patients had APD or ND on MRI at last follow up. In none of the patients APD and ND regressed or resolved. A deterioration of radiological ND was noted in 17 patients leading to overt clinical neuropsychological impairment in five.

CONCLUSIONS

Patients with HPT appear to be at high risk to develop permanent neuroendocrine consequences. Coordinated studies for patients with LCH and HP disease including thorough MRI monitoring and neuropsychological tests are needed.

Central diabetes insipidus as the inaugural manifestation of Langerhans cell histiocytosis: natural history and medical evaluation of 26 children and adolescents

CONTEXT

Isolated central diabetes insipidus (CDI) can be the first manifestation of Langerhans cell histiocytosis (LCH), creating diagnostic dilemmas such as dysgerminoma and other inflammatory lesions.

METHOD

In 2010, the French national LCH registry had enrolled 1236 LCH patients under 18 yr of age. Isolated CDI was the initial presentation of LCH in 26 patients. We reviewed their clinical and magnetic resonance imaging (MRI) features.

RESULTS

Median age at the diagnosis of CDI was 9.6 yr (1.8-16.3), and median follow-up after CDI diagnosis was 9.9 yr (3.5-26.6). In addition to CDI, two patients had visual field defects, four had secondary amenorrhea, and 11 had anterior pituitary deficiency. Cerebral imaging (including computed tomography in two cases), performed in 22 patients within 3 months of CDI diagnosis, showed pituitary stalk thickening in 14 patients, which was moderate (3.0-7 mm) in nine cases and marked (>7 mm) in five cases. In eight cases, the lesion extended to the floor of the third ventricle. One child with LCH presented with a mild enlarged sellar content. During follow-up, 22 patients developed extrapituitary involvement, mainly of bone (n = 15), lung (n = 9), and skin (n = 9). Pituitary biopsy was performed in eight cases and was conclusive in six cases.

CONCLUSIONS

Pituitary stalk thickening can be observed in LCH as well as lesions extending to the floor of the third ventricle. In all cases but one, the intrasellar content was not enlarged. Long-term follow-up with close attention to bone, skin, and lung disorders may lead to the diagnosis of LCH.

Incidence and pattern of radiological central nervous system Langerhans cell histiocytosis in children: a population based study

BACKGROUND

Patients with Langerhans cell histiocytosis (LCH) may develop neurodegeneration and other central nervous system (CNS) dysfunctions revealed by brain magnetic resonance imaging (MRI). We estimated the incidence and pattern of pathological brain MRI findings in a well-defined, population-based cohort of children with LCH.

METHODS

Among children under 15 years of age diagnosed with LCH in the Stockholm County during 1992-2001, brain MRI was performed at a single center in children with clinical and/or laboratory signs of CNS involvement, including endocrine dysfunction.

RESULTS

Out of the 29 children (16 males, 13 females) diagnosed with LCH, brain MRI was performed based on clinical indications in 16 children (55%) with either abnormal endocrine findings (n = 6), such as diabetes insipidus (n = 5), low IGF-1 (n = 1), or panhypopituitarism (n = 1), or clinical CNS symptoms (n = 10). CNS MRI abnormalities were demonstrated in eight children (28%), at a median time of 3.5 years after LCH diagnosis (range 1-11.4 years). Altogether 7 of the 29 children (24%) had MRI findings associated with neurodegeneration, corresponding to a minimal incidence of 2.1/10(6) children per year. Neurodegenerative abnormalities tended to be more frequent in patients with craniofacial involvement (P = 0.12).

CONCLUSIONS

The minimal annual incidence rate of neurodegenerative associated radiographic findings in LCH is estimated at 2.1/10(6) children (24% of all children with LCH). An important question is whether all patients with LCH, or certain forms of LCH, should be recommended for a late follow-up examination including MRI. In patients with CNS-LCH, neurological, neuropsychological, neurophysiological, neurochemical and neuroradiological follow-up assessment is suggested.

Neuropsychiatric manifestations in Langerhans' cell histiocytosis disease: a case report and review of the literature

The spectrum of the possible manifestations of Langerhans' cell histiocytosis in children is very wide, ranging from a simple rash to major multiorgan disease. There may be hypothalamic and pituitary dysfunction or more global neurological and neuropsychiatric manifestations when the central nervous system is affected. The cerebellum is preferentially affected for yet undetermined reasons. The clinical presentation includes motor dysfunction as well as cognitive, behavioral, and psychiatric expression of the ongoing neurodegeneration. We report a young patient with Langerhans' cell histiocytosis who underwent an unusual course of psychiatric deterioration.

Neurodegenerative central nervous system Langerhans cell histiocytosis and coincident hydrocephalus treated with vincristine/cytosine arabinoside

BACKGROUND

Central nervous system (CNS) complications of Langerhans cell histiocytosis (LCH) include mass lesions and a neurodegenerative (ND) syndrome with ataxia, dysarthria, dysmetria, learning and behavior difficulties and/or characteristic changes on brain MRIs. Hydrocephalus has rarely been reported in LCH. LCH lesions of the orbit, mastoid and temporal bones ("CNS-Risk" lesions) and diabetes insipidus predispose patients to ND-CNS-LCH. Treatment options have been limited and only a case series using trans-retinoic acid (ATRA) and intravenous immunoglobulin (IVIG) have been published.

METHODS

We have used cytosine arabinoside (ARA-C) with or without vincristine to treat eight patients with ND-CNS LCH.

PATIENTS

Seven male children and one young adult male with clinical and radiologic ND-CNS-LCH were treated with a regimen of vincristine 1.5 mg/m(2) on day 1 and ARA-C 100 mg/m(2) daily for 5 days or ARA-C alone monthly for 4-19 months. Seven patients were evaluated with an ataxia rating scale (ARS) and all with serial MRIs of the brain.

RESULTS

Five of seven patients had decreases in their ARS scores and/or decreased T2 hyperintense lesions on MRI images. Grade 2 neutropenia was the most frequent adverse event. Vincristine-associated neuropathy occurred in two patients. Hydrocephalus caused symptoms and signs that confounded the diagnosis and management of ND-CNS-LCH in all four patients affected with both.

CONCLUSIONS

Subtle changes in neurologic function may be complicated by hydrocephalus. Vcr/ARA-C or ARA-C were an effective therapies for some ND-CNS LCH patients. A clinical trial using this and possibly other modalities such as IVIG or ATRA should be done.

Biomarkers in the cerebrospinal fluid and neurodegeneration in Langerhans cell histiocytosis

BACKGROUND

Progressive neurodegeneration may result in potentially severe cognitive and motor dysfunctions as a complication of Langerhans cell histiocytosis (LCH), a suggested IL-17A-associated inflammatory condition. To detect this complication (CNS-LCH) early and to evaluate the potential efficacy of therapeutic interventions, biomarkers detecting and measuring ongoing neurodegeneration would be valuable. We evaluated cerebrospinal fluid (CSF) biomarkers of ongoing neurodegeneration in CNS-LCH patients.

PROCEDURE

Nine patients with endocrine, neuromotor, cognitive or/and behavioral abnormalities as well as neuroradiological evidence of CNS-LCH were evaluated 4-12 years after LCH diagnosis for CSF levels of neurofilament protein light chain (NF-L), glial fibrillary acid protein (GFAp), and total tau protein (TAU). Two patients were analyzed longitudinally. One hundred ten children with newly diagnosed acute lymphoblastic leukemia (ALL) served as controls.

RESULTS

NF-L, TAU, and GFAp levels were elevated in four, six, and eight of nine patients studied, respectively. NF-L (P < 0.001) and GFAp (P < 0.001) were higher in patients than in controls (TAU not analyzed in controls). The patient with most severe clinical and neuroradiological CNS-LCH displayed the highest levels of NF-L and GFAp whereas three patients without signs of systemic disease had low TAU levels and normal/slightly elevated NF-L. NF-L tended to be higher at radiological progression of neurodegeneration than at status quo (P = 0.07). Notably, we experienced frequent lumbar puncture complications in these patients.

CONCLUSIONS

CSF levels of NF-L, TAU, and GFAp appear to be elevated in CNS-LCH. It would be valuable if these markers were validated in order to serve as markers for early CNS-LCH, to monitor disease progression and to evaluate various treatment attempts for CNS-LCH.

Failure to treat obstructive hydrocephalus with endoscopic third ventriculostomy in a patient with neurodegenerative Langerhans cell histiocytosis

The second most frequent central nervous system involvement pattern in Langerhans cell histiocytosis (LCH) is a rare condition documented in a number of reports called "neurodegenerative LCH" (ND-LCH). Magnetic resonance images confirming the presence of the disease usually demonstrate striking symmetric bilateral hyperintensities predominantly in the cerebellum, basal ganglia, pons, and/or cerebral white matter. The authors here describe for the first time in the literature a patient with ND-LCH and concomitant hydrocephalus initially treated using endoscopic third ventriculostomy (ETV). This 9-year-old boy, who had undergone chemotherapy for skin and lung LCH without central nervous system involvement at the age of 10 months, presented with acute ataxia, headaches, and paraparesis and a 1-year history of gradually increasing clumsiness. Magnetic resonance images showed obstructive hydrocephalus at the level of the aqueduct of Sylvius and signs of ND-LCH. After registering high intracranial pressure (ICP) spikes with an intraparenchymal pressure monitor, an ETV was performed. A second ETV was required months later because of ostomy occlusion, and finally a ventriculoperitoneal shunt was placed because of ostomy reocclusion. Endoscopic third ventriculostomy was initially considered the treatment of choice to divert cerebrospinal fluid without leaving a ventriculoperitoneal shunt and to obtain biopsy specimens from the periinfundibular recess area. The third ventriculostomy occluded twice, and an endoscopic aqueduct fenestration was unsuccessful. The authors hypothesized that an inflammatory process related to late ND disease was responsible for the occlusions. Biopsy specimens from the infundibular recess and fornix column did not show histopathogical abnormalities. Increased ICP symptoms resolved with cerebrospinal fluid diversion. This case is the first instance of ND-LCH with hydrocephalus reported in the literature to date. Shunt placement rather than ETV seems to be the favorable choice in relieving elevated ICP.

Langerhans cell histiocytosis

The clinical manifestations of Langerhans cell histiocytosis have been recognized for more than a century. For most of that time, physicians have viewed the disease from different perspectives, interpreting portions of its clinical spectrum as if they were distinct and unrelated entities. More recently, Langerhans cell histiocytosis has been unified into a single concept, though the disease continues to defy traditional classification. By most accounts, Langerhans cell histiocytosis appears to be a morphologically benign proliferation of inflammatory cells that escapes regulatory control mechanisms. Studies from patients with all stages of the disease, however, document clonal proliferation of immune processing cells (i.e., Langerhans cells), suggesting a malignant disease process. The most common ophthalmic manifestation of Langerhans cell histiocytosis is a solitary lesion of orbital bone, which typically responds to minimally invasive therapy. The best management of solitary orbital Langerhans cell histiocytosis is debatable and has been complicated by its recent designation as a risk factor for central nervous system disease. This article summarizes recent developments in understanding the biology of Langerhans cell histiocytosis, reviews its ophthalmic manifestations, prognosis, and the controversy surrounding treatment of isolated orbital disease.

Pattern and course of neurodegeneration in Langerhans cell histiocytosis

OBJECTIVE

To explore the frequency and course of neurodegenerative central nervous system (CNS) disease in Langerhans cell histiocytosis (ND-LCH).

STUDY DESIGN

We studied 83 patients with LCH in whom magnetic resonance imaging (MRI) of the brain was performed at least twice for various clinical indications. We defined radiologic ND-LCH as an MRI pattern comprising bilateral symmetric lesions in the dentate nucleus of the cerebellum or basal ganglia.

RESULTS

Forty-seven of 83 patients (57%) had radiologic ND-LCH, at a median of 34 months (range 0-16 years) from the diagnosis of LCH. The MRI findings deteriorated in 31/47 (66%) patients over a median of 3 years (range 2 months to 12 years 6 months) and did not reverse in any patient. In 12 patients with radiologic ND-LCH (25%), clinical ND-LCH with overt symptoms were found 3 to 15 years (median 6 years) after initial LCH diagnosis. These symptoms included intention tremor, cerebellar ataxia, dysarthria, dysdiadochokinesis, concentration deficits, psychomotor retardation, severe headaches, and psychosis.

CONCLUSION

We conclude that radiologic ND-LCH is serious, not uncommon in patients studied by MRI, irreversible, and may be followed by severe clinical ND-LCH many years after the initial diagnosis of LCH.