Assessing the newly proposed MRI criteria for diagnosing sporadic Creutzfeldt-Jakob disease.

Sporadic Creutzfeldt-Jakob disease (sCJD) is a frequent differential diagnostic consideration in patients with rapidly progressive dementia (RPD). Fortunately, in the last 2 decades there has been substantial cumulative improvements in sCJD biomarkers, particularly those based on imaging and cerebrospinal fluid (CSF) interrogation. Brain MRI is a very frequently employed investigation in patients with RPD, often utilized quite early in the evaluation and thereby offering a potentially key role in prompting initial concerns for sCJD. Extant conventional MRI criteria for sCJD diagnosis are relatively stringent, requiring fluid attenuated inversion recovery (FLAIR) or diffusion weighted imaging (DWI) high signal changes in 2 or more cortical regions (excluding frontal) or in both the caudate and putamen. Challenging these conventional criteria, a recent publication described improved sensitivity and unchanged specificity if MRI criteria were arguably less rigorous, requiring DWI high signal changes in only 1 or more of 7 discrete brain regions: frontal, parietal, occipital or temporal cortices, as well as the caudate, putamen or thalamus. The aim of the current study was to test the diagnostic performance of this proposed change in MRI criteria in the Australian context and compare it with conventional criteria, as well as 2 other stringent sets of criteria, predicting that a similar improved sensitivity with unchanged specificity would be observed when the proposed criteria were utilized. Sixty-five definite sCJD cases were compared with 63 age- and sex-matched controls. Radiological review of all MRIs applying the different sets of MRI criteria was undertaken by a blinded neuroradiologist, very experienced in CJD interpretation, with independent assessment of 71 MRIs performed by a second blinded neuroradiologist less experienced in sCJD imaging findings. Our study found the sensitivity of the recently proposed MRI criteria (92.3%) to be comparable to that originally reported (90-95%) and also equivalent to the conventional MRI diagnostic criteria (92.3%), while the specificities were also quite similar between the conventional MRI criteria (87.3%) and proposed criteria (85.7%), with the latter lower than previously reported. Negative predictive values and positive predictive values were also very similar between the conventional and proposed MRI criteria. Other MRI criteria assessed were associated with unacceptably low sensitivity for clinical use. Inter-rater reliability as assessed by intra-class correlation coefficients (ICC) revealed moderate reliability for the conventional and proposed MRI criteria, modestly better in the former and when the frontal lobe was retained versus excluded in comparisons.

Central Conditions Mimicking Benign Paroxysmal Positional Vertigo: A Case Series.

BACKGROUND AND PURPOSE: Benign paroxysmal positional vertigo (BPPV) is the most common cause of positional vertigo. The term "benign" is consistent with a peripheral vestibular disorder that does not carry the potentially sinister sequelae of a central nervous system (CNS) cause. However, in 12% to 20% of cases, positional vertigo may be attributed to CNS pathology, including tumors of the cerebellum. CASE DESCRIPTION: Here, we present a series of 3 cases in which positional vertigo and nystagmus were the only presenting features in 2 cases of cerebellar tumor and 1 case of obstructive hydrocephalus. INTERVENTION: All patients underwent surgical intervention for removal of posterior fossa tumors or posterior fossa decompression for obstructive hydrocephalus. Following surgery, all 3 patients underwent a period of vestibular rehabilitation for postoperative motion sensitivity and balance impairment. OUTCOMES: Despite the continuing presence of central positioning nystagmus, all 3 patients recovered well, putatively with the aid of vestibular rehabilitation. DISCUSSION: The presence of central positioning nystagmus may be the sole presenting feature of serious neurological conditions such as posterior fossa tumor. It is recommended that a diagnosis of BPPV can only be made if Dix-Hallpike or supine roll maneuver elicits nystagmus that is consistent with BPPV. Any features of the nystagmus, which are not consistent with BPPV, should raise suspicion of central pathology, and warrant further investigation.Video Abstract available for more insights from the authors (see Video Abstract, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A265).

Novel Blood Biomarkers Are Associated with White Matter Lesions in Fragile X- Associated Tremor/Ataxia Syndrome.

BACKGROUND: The need for accessible cellular biomarkers of neurodegeneration in carriers of the fragile X mental retardation 1 (FMR1) premutation (PM) alleles. OBJECTIVE: To assess the mitochondrial status and respiration in blood lymphoblasts from PM carriers manifesting the fragile X-associated tremor/ataxia syndrome (FXTAS) and non-FXTAS carriers, and their relationship with the brain white matter lesions. METHODS: Oxygen consumption rates (OCR) and ATP synthesis using a Seahorse XFe24 Extracellular Flux Analyser, and steady-state parameters of mitochondrial function were assessed in cultured lymphoblasts from 16 PM males (including 11 FXTAS patients) and 9 matched controls. The regional white matter hyperintensity (WMH) scores were obtained from MRI. RESULTS: Mitochondrial respiratory activity was significantly elevated in lymphoblasts from PM carriers compared with controls, with a 2- to 3-fold increase in basal and maximum OCR attributable to complex I activity, and ATP synthesis, accompanied by unaltered mitochondrial mass and membrane potential. The changes, which were more advanced in FXTAS patients, were significantly associated with the WMH scores in the supratentorial regions. CONCLUSION: The dramatic increase in mitochondrial activity in lymphoblasts from PM carriers may represent either the early stages of disease (specific alterations in short-lived blood cells) or an activation of the lymphocytes under pathological situations. These changes may provide early, convenient blood biomarkers of clinical involvements.

Large anterior temporal Virchow-Robin spaces: unique MR imaging features.

INTRODUCTION: Large Virchow-Robin (VR) spaces may mimic cystic tumor. The anterior temporal subcortical white matter is a recently described preferential location, with only 18 reported cases. Our aim was to identify unique MR features that could increase prospective diagnostic confidence. METHODS: Thirty-nine cases were identified between November 2003 and February 2014. Demographic, clinical data and the initial radiological report were retrospectively reviewed. Two neuroradiologists reviewed all MR imaging; a neuropathologist reviewed histological data. RESULTS: Median age was 58 years (range 24-86 years); the majority (69 %) was female. There were no clinical symptoms that could be directly referable to the lesion. Two thirds were considered to be VR spaces on the initial radiological report. Mean maximal size was 9 mm (range 5-17 mm); majority (79 %) had perilesional T2 or fluid-attenuated inversion recovery (FLAIR) hyperintensity. The following were identified as potential unique MR features: focal cortical distortion by an adjacent branch of the middle cerebral artery (92 %), smaller adjacent VR spaces (26 %), and a contiguous cerebrospinal fluid (CSF) intensity tract (21 %). Surgery was performed in three asymptomatic patients; histopathology confirmed VR spaces. Unique MR features were retrospectively identified in all three patients. CONCLUSION: Large anterior temporal lobe VR spaces commonly demonstrate perilesional T2 or FLAIR signal and can be misdiagnosed as cystic tumor. Potential unique MR features that could increase prospective diagnostic confidence include focal cortical distortion by an adjacent branch of the middle cerebral artery, smaller adjacent VR spaces, and a contiguous CSF intensity tract.

White matter changes in patients with Parkinson's disease carrying small CGG expansion FMR1 alleles: a pilot study.

BACKGROUND/AIMS: Alleles of the FMR1 gene containing small expansions of the CGG-trinucleotide repeat comprise premutation and grey-zone alleles. Premutation alleles may cause late-onset Fragile X-associated tremor/ataxia syndrome attributed to the neurotoxic effect of elevated FMR1 transcripts. Our earlier data suggested that both grey-zone and low-end premutation alleles might also play a significant role in the acquisition of the parkinsonian phenotype due to mitochondrial dysfunction caused by elevated FMR1 mRNA toxicity. These data were obtained through clinical and molecular comparisons between carriers of grey-zone/low-end premutation alleles and group-matched non-carrier controls from patients with idiopathic Parkinson's disease (iPD). We aimed to explore the relationship between grey-zone alleles, parkinsonism and white matter changes. METHODS: This study compared the extent and severity of white matter hyperintensity (WMH) on magnetic resonance imaging, using a semi-quantitative method, between 11 grey-zone/low-end premutation carriers and 20 non-carrier controls with iPD from our earlier study. Relationships between WMH scores, and cognitive and motor test scores were assessed for carriers and non-carriers. RESULTS: Supratentorial WMH scores, and tremor and ataxia motor scores were significantly higher in carriers compared with disease controls. Moreover, some associations between cognitive decline and WMH scores were specific for each respective carrier status category. CONCLUSIONS: The results support our earlier claim that grey-zone alleles contribute to the severity of parkinsonism and white matter changes.

The Mediterranean diet improves hepatic steatosis and insulin sensitivity in individuals with non-alcoholic fatty liver disease.

BACKGROUND & AIMS: Non-alcoholic fatty liver disease (NAFLD) affects up to 30% of the population and signifies increased risk of liver fibrosis and cirrhosis, type 2 diabetes, and cardiovascular disease. Therapies are limited. Weight loss is of benefit but is difficult to maintain. We aimed at examining the effect of the Mediterranean diet (MD), a diet high in monounsaturated fatty acids, on steatosis and insulin sensitivity, using gold standard techniques. METHODS: Twelve non-diabetic subjects (6 Females/6 Males) with biopsy-proven NAFLD were recruited for a randomised, cross-over 6-week dietary intervention study. All subjects undertook both the MD and a control diet, a low fat-high carbohydrate diet (LF/HCD), in random order with a 6-week wash-out period in- between. Insulin sensitivity was determined with a 3-h hyperinsulinemic-euglycemic clamp study and hepatic steatosis was assessed with localized magnetic resonance (1)H spectroscopy ((1)H-MRS). RESULTS: At baseline, subjects were abdominally obese with elevated fasting concentrations of glucose, insulin, triglycerides, ALT, and GGT. Insulin sensitivity at baseline was low (M=2.7 ± 1.0 mg/kg/min(-1)). Mean weight loss was not different between the two diets (p=0.22). There was a significant relative reduction in hepatic steatosis after the MD compared with the LF/HCD: 39 ± 4% versus 7 ± 3%, as measured by (1)H-MRS (p=0.012). Insulin sensitivity improved with the MD, whereas after the LF/HCD there was no change (p=0.03 between diets). CONCLUSIONS: Even without weight loss, MD reduces liver steatosis and improves insulin sensitivity in an insulin-resistant population with NAFLD, compared to current dietary advice. This diet should be further investigated in subjects with NAFLD.

Evidence for the toxicity of bidirectional transcripts and mitochondrial dysfunction in blood associated with small CGG expansions in the FMR1 gene in patients with parkinsonism.

PURPOSE: Our previous results showed that both gray zone and lower end premutation range (40-85 repeats) fragile X mental retardation 1 (FMR1) alleles were more common among males with parkinsonism than in the general population. This study aimed to determine whether these alleles have a significant role in the manifestations and pathogenesis of parkinsonian disorders. METHODS: Detailed clinical assessment and genetic testing were performed in 14 male carriers of premutation and gray zone FMR1 alleles and in 24 noncarriers identified in a sample of males with parkinsonism. RESULTS: The premutation + gray zone carriers presented with more severe symptoms than disease controls matched for age, diagnosis, disease duration, and treatment. The Parkinson disease (Unified Parkinson's Disease Rating Scale) motor score and the measures of cognitive decline (Mini-Mental State Examination and/or Addenbrooke's Cognitive Examination Final Revised Version A scores) were significantly correlated with the size of the CGG repeat and the (elevated) levels of antisense FMR1 and Cytochrome C1 mRNAs in blood leukocytes. In addition, the carriers showed a significant depletion of the nicotinamide adenine dinucleotide, reduced dehydrogenase subunit 1 mitochondrial gene in whole blood. CONCLUSION: Small CGG expansion FMR1 alleles (gray zone and lower end premutation) play a significant role in the development of the parkinsonian phenotype, possibly through the cytotoxic effect of elevated sense and/or antisense FMR1 transcripts involving mitochondrial dysfunction and leading to progressive neurodegeneration.

Lymphoma, a great imitator in neurology.

The title "great imitator" refers to conditions which can cause varied manifestations and mimic many diseases. Lymphoma is worthy of this title. We describe three cases of lymphoma in which lymphoma mimicked other diseases causing neurological dysfunction, specifically sarcoidosis, vasculitis and infection respectively. Case 1 was a 66-year-old man with subacute progressive diplopia and gait disturbance and investigations revealing a supratentorial para-falcine soft tissue lesion, mid-thoracic cord enhancement and right axillary mass and an elevated serum ACE. Right axillary mass core biopsy was diagnostic of Burkitt lymphoma. Case 2 was a 50-year-old man with several weeks of constitutional symptoms and development of lower limb weakness and numbness, urinary retention and confusion while in hospital. MRI brain demonstrated multi-territory cerebral infarcts. Intravascular lymphoma was diagnosed on random skin biopsy. Case 3 was a 65-year-old man with several weeks of headache and diplopia on a background of previously treated Burkitt lymphoma. CSF analysis showed a lymphocytic pleocytosis and markedly low glucose with cytologic analysis negative for malignancy. Investigations for an infective cause were negative. FDG-PET demonstrated marked, disseminated spinal and cranial leptomeningeal disease and a multi-focal, intra-dural relapse of Burkitt lymphoma was diagnosed. The varied manifestations in our cases demonstrate the ability for lymphoma to mimic infective, inflammatory, granulomatous (including sarcoidosis) and neoplastic aetiologies. An elevated serum ACE appears insufficiently diagnostic to confirm sarcoidosis and tissue for histological examination should be sought whenever possible. When the diagnosis is uncertain, the possibility of this great imitator should be considered, especially for multi-focal disease.

Differential Progression of Motor Dysfunction Between Male and Female Fragile X Premutation Carriers Reveals Novel Aspects of Sex-Specific Neural Involvement.

Expansions of the CGG repeat in the non-coding segment of the FMR1 X-linked gene are associated with a variety of phenotypic changes. Large expansions (>200 repeats), which cause a severe neurodevelopmental disorder, the fragile x syndrome (FXS), are transmitted from the mothers carrying smaller, unstable expansions ranging from 55 to 200 repeats, termed the fragile X premutation. Female carriers of this premutation may themselves experience a wide range of clinical problems throughout their lifespan, the most severe being the late onset neurodegenerative condition called "Fragile X-Associated Tremor Ataxia Syndrome" (FXTAS), occurring between 8 and 16% of these carriers. Male premutation carriers, although they do not transmit expanded alleles to their daughters, have a much higher risk (40-50%) of developing FXTAS. Although this disorder is more prevalent and severe in male than female carriers, specific sex differences in clinical manifestations and progress of the FXTAS spectrum have been poorly documented. Here we compare the pattern and rate of progression (per year) in three motor scales including tremor/ataxia (ICARS), tremor (Clinical Tremor Rating scale, CRST), and parkinsonism (UPDRS), and in several cognitive and psychiatric tests scores, between 13 female and 9 male carriers initially having at least one of the motor scores ≥10. Moreover, we document the differences in each of the clinical and cognitive measures between the cross-sectional samples of 21 female and 24 male premutation carriers of comparable ages with FXTAS spectrum disorder (FSD), that is, who manifest one or more features of FXTAS. The results of progression assessment showed that it was more than twice the rate in male than in female carriers for the ICARS-both gait ataxia and kinetic tremor domains and twice as high in males on the CRST scale. In contrast, sex difference was negligible for the rate of progress in UPDRS, and all the cognitive measures. The overall psychiatric pathology score (SCL-90), as well as Anxiety and Obsessive/Compulsive domain scores, showed a significant increase only in the female sample. The pattern of sex differences for progression in motor scores was consistent with the results of comparison between larger, cross-sectional samples of male and female carriers affected with the FSD. These results were in concert with sex-specific distribution of MRI T2 white matter hyperintensities: all males, but no females, showed the middle cerebellar peduncle white matter hyperintensities (MCP sign), although the distribution and severity of these hyperintensities in the other brain regions were not dissimilar between the two sexes. In conclusion, the magnitude and specific pattern of sex differences in manifestations and progression of clinically recorded changes in motor performance and MRI lesion distribution support, on clinical grounds, the possibility of certain sex-limited factor(s) which, beyond the predictable effect of the second, normal FMR1 alleles in female premutation carriers, may have neuroprotective effects, specifically concerning the cerebellar circuitry.

Total and Regional White Matter Lesions Are Correlated With Motor and Cognitive Impairments in Carriers of the FMR1 Premutation.

This study explores the relationships between hemispheric and cerebellar white matter lesions and motor and cognitive impairments in male carriers of Fragile-X Mental Retardation 1 (FMR1) premutation alleles, and in a subgroup of these carriers affected with Fragile X-Associated Tremor/Ataxia syndrome (FXTAS). Regional and total white matter hyperintensities (wmhs) on MRI, assessed using semiquantitative scores, were correlated with three motor rating scales (ICARS, UPDRS, Tremor), and neuropsychological measures of non-verbal reasoning, working memory and processing speed, in a sample of 30 male premutation carriers aged 39-81 years, and separately in a subsample of 17 of these carriers affected with FXTAS. There were significant relationships between wmhs in the infratentorial region and all three motor scales, as well as several cognitive measures-Prorated IQ, Matrix Reasoning, Similarities, and the Symbol Digit Modalities Test (SDMT), in the total sample of carriers, as well as in the FXTAS group separately. This shows that whms within the infratentorial region correlates across the categories of clinical status with a range of motor and cognitive impairments. In the FXTAS group, there was a highly significant relationship between supratentorial (periventricular) lesions and parkinsonism, and between both periventricular and supratentorial deep white matter and ICARS ataxia score. These findings further support the relevance of white matter changes in different brain regions to the motor and cognitive deficits across the spectrum of premutation involvement. Future longitudinal studies using larger sample sizes will be necessary to examine the factors that lead to conversion to a greater extent of neurological involvement as seen in the progression across the FXTAS spectrum.

Brainstem distortion from postoperative cerebellar herniation through a dural and bony defect.

We report a patient with a cerebellar encephalocele following excision of a cerebellar metastasis. This is a life-threatening condition that may be prevented with adequate dural and bony closure.

Spontaneous third ventriculostomy.

Spontaneous ventriculostomy (SV) is a rare condition where there is a spontaneous communication between the ventricle and the subarachnoid space as a result of hydrocephalus. Only four cases of SV through the floor of the third ventricle have been previously reported. Two further cases are presented and the literature reviewed.

The Spectrum of Neurological and White Matter Changes and Premutation Status Categories of Older Male Carriers of the FMR1 Alleles Are Linked to Genetic (CGG and FMR1 mRNA) and Cellular Stress (AMPK) Markers.

The fragile X premutation (PM) allele contains a CGG expansion of 55-200 repeats in the FMR1 gene's promoter. Male PM carriers have an elevated risk of developing neurological and psychiatric changes, including an approximately 50% risk of the fragile X-associated tremor/ataxia syndrome (FXTAS). The aim of this study was to assess the relationships of regional white matter hyperintensities (wmhs) semi-quantitative scores, clinical status, motor (UPDRS, ICARS, Tremor) scales, and cognitive impairments, with FMR1-specific genetic changes, in a sample of 32 unselected male PM carriers aged 39-81 years. Half of these individuals were affected with FXTAS, while the non-FXTAS group comprised subcategories of non-affected individuals and individuals affected with non-syndromic changes. The dynamics of pathological processes at the cellular level relevant to the clinical status of PM carriers was investigated using the enzyme AMP-activated protein kinase (AMPK), which is a highly sensitive cellular stress-sensing alarm protein. This enzyme, as well as genetic markers - CGG repeat number and the levels of the FMR1 mRNA - were assessed in blood lymphoblasts. The results showed that the repeat distribution for FXTAS individuals peaked at 85-90 CGGs; non-FXTAS carriers were distributed within the lowest end of the PM repeat range, and non-syndromic carriers assumed an intermediate position. The size of the CGG expansion was significantly correlated, across all three categories, with infratentorial and total wmhs and with all motor scores, and the FMR1 mRNA levels with all the wmh scores, whilst AMPK activity showed considerable elevation in the non-FXTAS combined group, decreasing in the FXTAS group, proportionally to increasing severity of the wmhs and tremor/ataxia. We conclude that the size of the CGG expansion relates to the risk for FXTAS, to severity of infratentorial wmhs lesions, and to all three motor scale scores. FMR1 mRNA shows a strong association with the extent of wmhs, which is the most sensitive marker of the pathological process. However, the AMPK activity findings - suggestive of a role of this enzyme in the risk of FXTAS - need to be verified and expanded in future studies using larger samples and longitudinal assessment.

Creation of a Large Adipose Tissue Construct in Humans Using a Tissue-engineering Chamber: A Step Forward in the Clinical Application of Soft Tissue Engineering.

Tissue engineering is currently exploring new and exciting avenues for the repair of soft tissue and organ defects. Adipose tissue engineering using the tissue engineering chamber (TEC) model has yielded promising results in animals; however, to date, there have been no reports on the use of this device in humans. Five female post mastectomy patients ranging from 35 to 49years old were recruited and a pedicled thoracodorsal artery perforator fat flap ranging from 6 to 50ml was harvested, transposed onto the chest wall and covered by an acrylic perforated dome-shaped chamber ranging from 140 to 350cm(3). Magnetic resonance evaluation was performed at three and six months after chamber implantation. Chambers were removed at six months and samples were obtained for histological analysis. In one patient, newly formed tissue to a volume of 210ml was generated inside the chamber. One patient was unable to complete the trial and the other three failed to develop significant enlargement of the original fat flap, which, at the time of chamber explantation, was encased in a thick fibrous capsule. Our study provides evidence that generation of large well-vascularized tissue engineered constructs using the TEC is feasible in humans.

Anterior visual pathway cavernous malformations.

Anterior visual pathway cavernous malformations (CM) are rare diagnoses with poorly-defined natural history and management. A systematic review of all reports of anterior visual pathway CM was performed to identify all English-language articles with histopathologically-proven anterior visual pathway CM published from 1950 to December 2013. Patient demographics, presenting symptoms, CM location, treatment modality and clinical outcome were recorded and analyzed. The case of a 60-year-old woman from our institution with acute-on-chronic visual disturbance secondary to visual pathway CM is presented. Including the current patient, 70 cases of anterior visual pathway CM have been published to our knowledge. The average patient age is 34.8 ± standard deviation of 14.2 years, with a female preponderance (n = 37, 52.9%). The majority of patients had an acute (n = 44; 62.9%; 95% confidence interval [CI] 0.51-0.73) onset of symptoms. In at least 55.6% (n = 40) of patients, the cause of visual disturbance was initially misdiagnosed. The majority (91.4%; n = 64) of patients underwent craniotomy, with complete resection and subtotal resection achieved in 53.1% (n = 34; 95%CI 0.41-0.65) and 17.2% (n = 11; 95%CI 0.10-0.28) of all surgical patients, respectively. Comparing surgically managed patients, complete resection improved visual deficits in 59.0% (n = 20; 95%CI 0.42-0.75), while subtotal resection improved visual deficits in 50.0% (n = 5; 95%CI 0.24-0.76; p = 0.62). CM is an important differential diagnosis for suprasellar lesions presenting with visual disturbance. A high index of suspicion is required in its diagnosis. Expeditious operative management is recommended to improve clinical outcomes.

Intraventricular CNS lesions: A pictorial essay.

Intraventricular lesions of the central nervous system (CNS) can present a diagnostic challenge due to a range of differential diagnoses and radiological appearances. Both CT and MRI imaging findings, in combination with location and patient's age, can help limit the differentials. This pictorial essay presents the salient radiological features, location and demographics of the more common intraventricular lesions of the brain.

Meningoencephalomyelitis with vasculitis due to varicella zoster virus: a case report and review of the literature.

Varicella zoster virus (VZV) encephalitis is associated with large or small vessel vasculopathy. We report the case of a 67-year-old woman with a history of non-Hodgkin's lymphoma and cancers of the breast and colon, who presented with a zosteriform rash and Brown-Sequard syndrome. Despite 10 days therapy with intravenous acyclovir, meningoencephalitis developed and the patient died 15 days after onset of neurological symptoms. Autopsy showed meningoencephalomyelitis with necrotising vasculitis of leptomeningeal vessels, which is a rare complication of VZV, and we review the literature of the nine similar published cases. Polymerase chain reaction of cerebrospinal fluid for VZV was negative 6 days after onset of neurological symptoms, but became positive by day 10. Only one multinucleated giant cell with intranuclear Cowdry type A inclusions was seen within an endothelial cell in a leptomeningeal vessel involved by vasculitis.

Unusual case of skull metastasis from hepatocellular carcinoma.

Hepatocellular carcinoma with a skull metastasis is a rare clinical entity especially in Western countries. The authors of the present article report a case of solitary skull metastasis from hepatocellular carcinoma in a 75-year-old lady who had no prior history of the primary disease or liver dysfunction. The clinicopathological and radiological features are reviewed and discussed.