POS0490 USEFULNESS OF MHC-II IMMUNO-STAINING ON MUSCLE BIOPSIES IN IDIOPATHIC INFLAMMATORY MYOPATHIES

Background

Idiopathic inflammatory myopathies (IIMs) constitute a group of acquired muscular diseases that occur during childhood and adulthood, exhibit a variety of phenotypes and are potentially life-threatening. IIM diagnosis considers clinical, serological, and histological data. Muscle pathological analysis of IIM patients gives relevant elements for the diagnosis (immune cell infiltrate, vascular and connective tissues, as well as myofiber morphology). Immunochemistry (IHC) labeling for major histocompatibility complex class I (MHC-I), and C5b9, that are negative in normal muscle, appeared of interest in IIM diagnosis and the understanding of IIM pathogenesis. In normal muscle, myofibers are negative for MHC-II IHC. Its interest in the neuropathological exam of IIM muscle remains to be better characterized.

Objectives

This study aims to analyze the pattern of MHC-II expression in various IIMs.

Methods

A historical cohort was designed using the MYOLYON register (IIM patients diagnosed between 2016 and 2020 at the University Hospital of Lyon, France). Inclusion criteria were IIM diagnosis that was established histologically and available frozen muscle samples for additional analyses. Exclusion criterium was any treatment before muscle biopsy. Demographical data and final diagnosis were collected retrospectively from medical records. A centralized, standardized, and blind analysis of muscle MHC-II immuno-staining was conducted to define the various patterns of MHC-II by myofibers and by capillaries. The study complied with ethical requirements.

Results

Seventy-three patients were included: 23 dermatomyositis (DM), 13 anti-synthetase syndrome (ASS), 13 immune-mediated necrotizing myopathies (IMNM), 13 inclusion body myositis (IBM), and 11 overlap myositis (OM). MHC-II immuno-staining of myofibers or capillaries was abnormal for 91.8% of the analyzed biopsies (Figure 1). The analysis of MHC-II myofiber immuno-staining revealed distinguishable patterns according to IIM subtype: the labeling was diffuse in IBM (69.2%, n=9/13), perifascicular in ASS (61.5%, n=8/13), and variable in OM (patchy for 27.3% n=3/11 or clustered for 36.4%, n=4/11). MHC-II immuno-staining was negative in IMNM (84.6%, n=11/13) and in DM (47.8%, n=11/23). DM exhibiting positive MHC-II myofibers (n=12) were associated with the presence of anti-TIF1γ, anti-NXP2 and anti-SAE auto antibodies (n=5, n=3 and n=2, respectively). Among the 12 patients, there were juvenile cases (n=5, 41.7%) or DM associated with ongoing neoplasia (n=4, 33.3%). Three main architectures were described for capillaries: giant, leaky and capillary dropout. Patterns of MHC-II positive capillaries were the following: DM was characterized by capillary dropout (68.2%), IMNM showed leaky capillaries (75.0%), IBM giant capillaries (66.7%), ASS exhibited both giant (61.5%) and/or leaky (58.3%) capillaries, while OM showed giant (63.6%) or/and leaky (80.0%) capillaries and capillaries dropout (60.0%).

Conclusion

The present work establishes the usefulness of MHC-II immuno-staining for IIM diagnosis, and gives additional elements on the impairment of myofibers and capillaries in the various IIM subgroups. MHC-II expression is known to be induced by inflammatory cytokine such as interferon type II. This could be linked to myofiber and/or capillary impairment in some IIMs, such as IBM, ASS and OM. These results also support the implication of vasculopathy in IIM pathogenesis, with various structural and cellular consequences regarding the different subgroups. Finally, MHC-II immuno-staining in IIM muscle biopsies enables a foremost analysis of myofibers and capillaries, and represents an additional biomarker to distinguish IIM subgroups.

References

[1]De Bleecker, J.L. et al. 205th ENMC International Workshop: Pathology diagnosis of idiopathic inflammatory myopathies part II 28-30 March 2014, Naarden, The Netherlands. Neuromuscul Disord 2015, 25, 268-272.

Disclosure of Interests

None declared.

POS0862 INAUGURAL DROPPED HEAD SYNDROME AND CAMPTOCORMIA IN INFLAMMATORY MYOPATHIES

Background

The idiopathic inflammatory myopathies (IIMs) are a heterogeneous group of diseases that can affect the muscles, skin, lungs, heart, and joints. Increase knowledge about histopathological findings, clinical manifestations and auto-antibodies have allowed further novel classification of IIMs. Today, the main IMs subgroups are: dermatomyositis (DM), inclusion body myositis (IBM), immune-mediated necrotizing myopathies (IMNM), overlap myositis (OM) and immune-checkpoint inhibitor-related myositis (ICIrm). Axial muscle involvement results either in a “Dropped Head Syndrome (DHS)”, with a marked weakness of the neck extensors, or in a camptocormia (CC), with a weakness of the thoracolumbar paraspinal muscles. This atypical presentation is poorly described in the course of IMs while it may results in a major disability, and may lead to myositis diagnosis delay.

Objectives

This study aimed to describe IMs revealed by DHS and/or CC. Secondary outcomes were to define subgroups of patients according to clinical, biological and histopathological characteristics. Then, the effects of treatments used were analyzed.

Methods

A historical cohort was designed using the register MYOLYON which includes all IMs followed at the University Hospital of Lyon (France) between 2000 and 2021. All patients with IM revealed by DHS and/or CC and having an histologically proven IMs were included, after exclusion of alternative (e.g., myasthenia gravis, motoneuron disease). Clinical, biological, immunological, histopathological data as well as outcome and care were collected through a standardized form. Agreement for the study was obtained from the French Ministry of the Research and the study was approved by the Local Research Ethics Committee.

Results

Twenty-two patients were fully characterized: DM (n=4), IBM (n=7), OM (n=8), ICIrm (n=2) and one myositis with anti-Hu antibodies. Two groups of patients were identified according to the age at first symptoms and to the type of muscle axial involvement (e.g, DHS and/or CC). Before the age of 70 (n=13/22), the two most common diagnoses (n=11/13) were DM (n=4/4) and OM (n=7/8). Axial muscle involvement was diffuse (DHS and CC) in 10/13 patients. After 70 years old (n=9/22), there were a majority of IBM (n=6/9) and all cases of ICIrm (n=2). Axial involvement was restricted to one group of muscles (DHS or CC) in 5/9 patients. Finally, 77% (17/22) of patients had refractory disease and required a second line treatment (e.g, immunoglobulins). All of these results are summarized in the Figure 1.

Figure 1.

Conclusion

While IM diagnosis is challenging in the presence of inaugural axial involvement, these results highlight the subset of IM to be considered according to the age at first symptoms and the type of axial involvement (e.g., DHS and/or CC).

References

[1]Mariampillai, K. et al. Development of a New Classification System for Idiopathic Inflammatory Myopathies Based on Clinical Manifestations and Myositis-Specific Autoantibodies. JAMA Neurol75, 1528-1537 (2018).

[2]Landon-Cardinal, O. et al. Recognising the spectrum of scleromyositis: HEp-2 ANA patterns allow identification of a novel clinical subset with anti-SMN autoantibodies. RMD Open6 (2020).

[3]Suarez, G.A. & Kelly, J.J., Jr. The dropped head syndrome. Neurology42, 1625-1627 (1992).

[4]Oerlemans, W.G. & de Visser, M. Dropped head syndrome and bent spine syndrome: two separate clinical entities or different manifestations of axial myopathy? J Neurol Neurosurg Psychiatry65, 258-259 (1998).

Disclosure of Interests

None declared

Low expression of ANT1 confers oncogenic properties to rhabdomyosarcoma tumor cells by modulating metabolism and death pathways

Rhabdomyosarcoma (RMS) is the most frequent form of pediatric soft-tissue sarcoma. It is divided into two main subtypes: ERMS (embryonal) and ARMS (alveolar). Current treatments are based on chemotherapy, surgery, and radiotherapy. The 5-year survival rate has plateaued at 70% since 2000, despite several clinical trials. RMS cells are thought to derive from the muscle lineage. During development, myogenesis includes the expansion of muscle precursors, the elimination of those in excess by cell death and the differentiation of the remaining ones into myofibers. The notion that these processes may be hijacked by tumor cells to sustain their oncogenic transformation has emerged, with RMS being considered as the dark side of myogenesis. Thus, dissecting myogenic developmental programs could improve our understanding of RMS molecular etiology. We focused herein on ANT1, which is involved in myogenesis and is responsible for genetic disorders associated with muscle degeneration. ANT1 is a mitochondrial protein, which has a dual functionality, as it is involved both in metabolism via the regulation of ATP/ADP release from mitochondria and in regulated cell death as part of the mitochondrial permeability transition pore. Bioinformatics analyses of transcriptomic datasets revealed that ANT1 is expressed at low levels in RMS. Using the CRISPR-Cas9 technology, we showed that reduced ANT1 expression confers selective advantages to RMS cells in terms of proliferation and resistance to stress-induced death. These effects arise notably from an abnormal metabolic switch induced by ANT1 downregulation. Restoration of ANT1 expression using a Tet-On system is sufficient to prime tumor cells to death and to increase their sensitivity to chemotherapy. Based on our results, modulation of ANT1 expression and/or activity appears as an appealing therapeutic approach in RMS management.

[Focal myositis: An unknown disease]

Focal myositis are inflammatory muscle diseases of unknown origin. At the opposite from the other idiopathic inflammatory myopathies, they are restricted to a single muscle or to a muscle group. They are not associated with extramuscular manifestations, and they have a good prognosis without any treatment. They are characterized by a localized swelling affecting mostly lower limbs. The pseudo-tumor can be painful, but is not associated with a muscle weakness. Creatine kinase level is normal. Muscle MRI shows an inflammation restricted to a muscle or a muscle group. Muscle biopsy and pathological analysis remain necessary for the diagnosis, showing inflammatory infiltrates composed by macrophages and lymphocytes without any specific distribution within the muscle. Focal overexpression of HLA-1 by the muscle fibers is frequently observed. The muscle biopsy permits to rule out differential diagnosis such a malignancy (sarcoma). Spontaneous remission occurs within weeks or months after the first symptoms, relapse is unusual.

Truncating mutations on myofibrillar myopathies causing genes as prevalent molecular explanations on patients with dilated cardiomyopathy

Dilated cardiomyopathy (DCM) is one of the leading causes of heart failure with high morbidity and mortality. More than 40 genes have been reported to cause DCM. To provide new insights into the pathophysiology of dilated cardiomyopathy, a next-generation sequencing (NGS) workflow based on a panel of 48 cardiomyopathies-causing genes was used to analyze a cohort of 222 DCM patients. Truncating variants were detected on 63 unrelated DCM cases (28.4%). Most of them were identified, as expected, on TTN (29 DCM probands), but truncating variants were also identified on myofibrillar myopathies causing genes in 17 DCM patients (7.7% of the DCM cohort): 10 variations on FLNC and 7 variations on BAG3 . This study confirms that truncating variants on myofibrillar myopathies causing genes are frequently associated with dilated cardiomyopathies and also suggest that FLNC mutations could be considered as a common cause of dilated cardiomyopathy. Molecular approaches that would allow to detect systematically truncating variants in FLNC and BAG3 into genetic testing should significantly increase test sensitivity, thereby allowing earlier diagnosis and therapeutic intervention for many patients with dilated cardiomyopathy.

Focal myositis: A review

Amongst the heterogeneous group of inflammatory myopathies, focal myositis stands as a rare and benign dysimmune disease. Although it can be associated with root and/or nerve lesions, traumatic muscle lesions and autoimmune diseases, its triggering factors remain poorly understood. Defined as an isolated inflammatory pseudotumour usually restricted to one skeletal muscle, clinical presentation of focal myositis is that of a rapidly growing solitary mass within a single muscle, usually in the lower limbs. Electromyography shows spontaneous activity associated with a myopathic pattern. MRI reveals a contrast enhanced enlarged muscle appearing hyper-intense on FAT-SAT T2 weighted images. Adjacent structures are spared and there are no calcifications. Serum creatine kinase (CK) levels are usually moderately augmented and biological markers of systemic inflammation are absent in most cases. Pathological histological features include marked variation in fibre size, inflammatory infiltrates mostly composed of T CD4+ lymphocytes and macrophages, degenerating/regenerating fibres and interstitial fibrosis. Differential diagnoses are numerous and include myositis of other origin with focal onset. Steroid treatment should be reserved for patients who present with major pain, nerve lesions, associated autoimmune disease, or elevated C reactive protein or CK.

Multiple acyl-CoA dehydrogenase deficiency (MADD) as a cause of late-onset treatable metabolic disease

INTRODUCTION

Late-onset multiple acyl-CoA dehydrogenase deficiency (MADD) is a rare, treatable, beta-oxidation disorder responsible for neuromuscular symptoms in adults. This case series describes the clinical and biochemical features of 13 French patients with late-onset MADD.

METHODS AND RESULTS

Thirteen ambulant patients (eight women, five men), with a median age at onset of 27 years, initially experienced exercise intolerance (n=9), isolated muscle weakness (n=1) and a multisystemic pattern with either central nervous system or hepatic dysfunction (n=3). During the worsening period, moderate rhabdomyolysis (n=5), a pseudomyasthenic pattern (n=5) and acute respiratory failure (n=1) have been observed. Weakness typically affected the proximal limbs and axial muscles, and there was sometimes facial asymmetry (n=3). Moderate respiratory insufficiency was noted in one case. Median baseline creatine kinase was 190IU/L. Lactacidemia was sometimes moderately increased at rest (3/10) and after exercise (1/3). The acylcarnitine profile was characteristic, with increases in all chain-length acylcarnitine species. Electromyography revealed a myogenic pattern, while muscle biopsy showed lipidosis, sometimes with COX-negative fibers (n=2). The mitochondrial respiratory chain was impaired in five cases, with coenzyme Q10 decreased in two cases. All patients harbored mutations in the ETFDH gene (four homozygous, seven compound heterozygous, two single heterozygous), with nine previously unidentified mutations. All patients were good responders to medical treatment, but exercise intolerance and/or muscular weakness persisted in 11 of them.

CONCLUSION

Late-onset forms of MADD may present as atypical beta-oxidation disorders. Acylcarnitine profiling and muscle biopsy remain the most decisive investigations for assessing the diagnosis. These tests should thus probably be performed more widely, particularly in unexplained cases of neuromuscular and multisystemic disorders.

[Exercise-induced muscle pain due to phosphofrutokinase deficiency: Diagnostic contribution of metabolic explorations (exercise tests, 31P-nuclear magnetic resonance spectroscopy)]

INTRODUCTION

Muscle phosphofructokinase deficiency, the seventh member of the glycogen storage diseases family, is also called Tarui's disease (GSD VII).

METHODS

We studied two patients in two unrelated families with Tarui's disease, analyzing clinical features, CK level, EMG, muscle biopsy findings and molecular genetics features. Metabolic muscle explorations (forearm ischemic exercise test [FIET]; bicycle ergometer exercise test [EE]; 31P-nuclear magnetic resonance spectroscopy of calf muscle [31P-NMR-S]) are performed as appropriate.

RESULTS

Two patients, a 47-year-old man and a 38-year-old woman, complained of exercise-induced fatigue since childhood. The neurological examination was normal or showed light weakness. Laboratory studies showed increased CPK, serum uric acid and reticulocyte count without anemia. There was no increase in the blood lactate level during the FIET or the EE although there was a light increase in the respiratory exchange ratio during the EE. 31P-NMR-S revealed no intracellular acidification or accumulated intermediates such as phosphorylated monoesters (PME) known to be pathognomic for GSD VII. Two new mutations were identified.

DISCUSSION

FIET and EE were non-contributive to diagnosis, but 31P-NMR provided a characteristic spectra of Tarui's disease, in agreement with phosphofructokinase activity level in erythrocytes. Muscle biopsy does not always provide useful information for diagnosis. In these two cases, genetic studies failed to establish a genotype-phenotype correlation.

CONCLUSION

The search for phosphofructokinase deficiency should be continued throughout life in adults experiencing fatigability or weakness because of the severe disability for daily life activities caused by the late onset form.

Diffusion tensor-MRI evidence for extra-axonal neuronal degeneration in caudate and thalamic nuclei of patients with multiple sclerosis

BACKGROUND AND PURPOSE

MS is an inflammatory demyelinating disease affecting both WM and GM. While WM lesions are easily visualized by conventional MR imaging, the detection of GM alterations remains challenging. This diffusion tensor MR imaging study aimed to detect and characterize diffuse microscopic alterations in 2 deep GM structures, the caudate nucleus and the thalamus, in patients with RR and SP MS. The relationship between diffusivity markers, and atrophy of the caudate and the thalamus, as well as brain lesion load and clinical status of the patients was also explored.

MATERIALS AND METHODS

Twenty-three RR and 18 SP patients, along with 27 healthy controls, underwent MR imaging examination including anatomic and DTI acquisitions. Volumes, mean FA, and MD of the caudate and the thalamus, as well as WM lesion volumes, were assessed.

RESULTS

FA was significantly (P < .001) increased in the caudate and the thalamus of patients with MS compared with controls, and was higher in SP compared with RR patients. Increased FA was associated with volume decreases of caudate (r = -0.712; P < .001) and thalamus (r = -0.407; P < .01) in patients with MS. WM T2 lesion load was significantly associated with caudate (r = 0.611; P < .001) and thalamic (r = 0.354; P < .05) FA. Caudate FA, and, to a lesser extent, thalamic FA, were associated with functional deficits, as measured by EDSS and MSFC.

CONCLUSIONS

Increased FA in the caudate and the thalamus may constitute a sensitive marker of MS pathologic processes, such as loss of dendrites and/or swelling of neuronal cell bodies.

Brain immunohistopathological study in a patient with anti-NMDAR encephalitis

BACKGROUND AND PURPOSE

Anti-N-methyl-D-asparate (NMDA) receptor encephalitis is thought to be antibody-mediated. To perform an immunohistopathological study of the inflammatory reaction in a brain biopsy performed before immunomodulatory treatments in a patient with anti-NMDA receptor encephalitis.

METHODS

An immunohistochemical study was performed using CD3, CD68, CD20, CD138 and CD1a antibodies.

RESULTS

Prominent B-cell cuffing was present around brain vessels accompanied by some plasma cells, while macrophages and T cells were scattered throughout the brain parenchyma.

CONCLUSION

These findings suggest that the B cells interact with the T cells and are involved in antibody secretion by the plasma cells.

Primary angiitis of the central nervous system: response to mycophenolate mofetil

Primary angiitis of the central nervous system (PACNS) is a rare inflammatory disease restricted to the CNS of unknown cause. Clinical presentation and evolution are highly variable with potentially fluctuating signs and symptoms. Brain imaging often shows supratentorial ischaemic lesions. Definite diagnosis is established by brain biopsy. Treatment usually combines glucocorticosteroids and cyclophosphamide. A case of PACNS is reported here, which was proved by a brain biopsy and characterised by unusually prominent involvement of the posterior cerebral fossa. Successful treatment with mycophenolate mofetil in combination with steroids is described.

[Structural anatomy of cranial nerves (V, VII, VIII, IX, X)]

This study reports a review of the literature on the structural anatomy of the Vth, VIIth, VIIIth, IXth, and Xth cranial nerves, known to harbor dysfunction syndromes in humans. Because these dysfunctions are hypothesized to be caused by neurovascular conflicts at the root entry/exit zone and the transitional zone between central and peripheral myelinization, this investigation focused on the study and description of this junction. All the cranial nerves, except the optic and olfactory nerves, which are considered to be more a direct expansion of the central nervous system, have a transitional zone between central myelin (coming from oligodendrocytes) and peripheral myelin (produced by Schwann cells). The human studies reported in the literature argue in favor of a dome-shaped transitional zone directed to the periphery. It seems that this junctional region is situated more peripherally in sensory nerves than in motor nerves. The transitional zone is situated very peripherally for the cochlear and vestibular nerves, and on the contrary very close to its exit from the brain stem for the facial nerve.

Diffusion-weighted imaging in brain aspergillosis

Brain aspergillosis is a rare pathology, occurring mainly in immunocompromised patients, responsible for multiple cerebral septic infarctions. Some researchers have described magnetic resonance (MR) findings in cerebral invasive aspergillosis, but diffusion-weighted imaging (DWI) has rarely been reported, especially in typical non-enhancing lesions, while it may be helpful for early differential diagnosis and may allow earlier antifungal treatment. We describe three cases of patients presenting brain aspergillosis, with MR imaging including diffusion-weighted sequences and apparent diffusion coefficient (ADC) cartography. The three patients described in this study presented a total of 23 circular lesions, and one patient presented an infarction area in the territory of the right middle cerebral artery. Lesions were ring-enhancing for one patient, and presented no enhancement for the other two. Eleven lesions were very bright on DWI, with reduced ADC values. Twelve lesions, either enhancing or not enhancing, presented a 'target-like' aspect with central and peripheral hypointense areas on DWI, corresponding to higher ADC value areas, and intermediate marked hypersignal on DWI. This typical aspect of aspergillosis lesions on DWI may allow early diagnosis and treatment of cerebral aspergillosis, and is helpful for differentiating aspergillosis lesions from other infectious or malignant lesions affecting immunocompromised patients.

Apport de la tomographie par émission de positons pour le diagnostic de sarcoïdose au cours d'une myopathie granulomateuse

INTRODUCTION

Granulomatous myositis is a rare condition that has been described in association with sarcoidosis. In the absence of sarcoidosis or other underlying disease, a diagnosis of isolated granulomatous myositis is considered.

OBSERVATION

A 61-year-old African man presented with progressive limitation in running and proximal atrophy of the lower limbs for the past year. Quadricipital muscle biopsy revealed non-caseating epithelioid granulomas and multinuclear giant cells. Whole body fluorodeoxyglucose positron emission tomography ((18)FDG-PET) revealed hypermetabolic activity of salivary and lachrymal glands, and mild hypermetabolism in the mediastinal lymph nodes. Minor salivary gland biopsy was consistent with sarcoidosis.

CONCLUSION

To our knowledge, this is the first reported case of sarcoid myopathy demonstrating the diagnostic usefulness of (18)FDG-PET.

[Family study allows more optimistic prognosis and genetic counselling in a child with a deletion of exons 50-51 of the dystrophin gene]

INTRODUCTION

In frame deletions of exons encoding the central rod domain of dystrophin have been associated with a highly variable phenotype, including asymptomatic individuals. The lack of family history impairs accurate genetic counselling.

OBSERVATION

We report on a 4-year-old child suffering from transient episodes of limping at the age of 2 and several episodes of fall since the age of 3. Clinical examination did not show muscle weakness. CPK levels were increased (1300 UI). EMG was normal. Muscle histology showed a rhabdomyolysis without features of muscular dystrophy. Immunolabelling for dystrophin, merosin and dysferlin were normal. Western blot analysis of muscular proteins showed reduced-size dystrophin bands and a slightly reduced intensity for dystrophin, alpha and gamma-sarcoglycan. Multiplex PCR of the dystrophin gene showed an in-frame deletion of exons 50-51, predicted to be associated to a Becker type of dystrophinopathy. Intragenic markers and quantitative PCR suggested maternal inheritance. This was confirmed by testing the maternal grand-parents, revealing that the asymptomatic 69-year-old grand father was a carrier. Three additional healthy males, whose ages ranged from 28 to 55 years and who were asymptomatic, also carried the mutation. The proband became spontaneously asymptomatic and cardiac echography was normal. In light of these data, genetic counselling was more reassuring and the mutation carrier maternal aunt, who was pregnant, decided to continue the pregnancy.

CONCLUSION

This case report emphasizes the importance of family molecular analysis, especially in males from the maternal lineage, for genetic counselling of dystrophinopathies associated to atypical features or to an isolate increase of muscular enzymes level in a young boy with no positive family history.

IRM de diffusion-perfusion dans l’évaluation des lymphomes cérébraux

Because of the increasing incidence of cerebral lymphoma, it is critical for patient management to recognize the MR features of this disease. We present the characteristic morphological and functional MRI features of this tumor. The findings on MRI studies, including morphological, diffusion and perfusion imaging, performed in 9 biopsy-proven cases of cerebral lymphoma with 13 lesions are presented and analyzed, and are discussed in comparison with published literature data. All patients underwent diffusion-weighted imaging with a single shot echo-planar pulse sequence. Dynamic susceptibility-contrast MRI was performed using a T2*-weighted gradient-echo echo-planar sequence after intravenous injection of chelates of gadolinium at the rate of 6 ml/s and a temporal resolution of 1 second. All cases of cerebral lymphoma appeared hypointense or isointense on T1-weighted images and in 75% of cases iso- or hypointense on T2-weighted images. All lesions enhanced except one in a patient receiving steroid therapy. On diffusion-weighted images, tumours were hyperintense with normal or decreased ADC values (0.717+/-0.152.10-3 mm2/sec, range: 0.550-1.014) and an ADC ratio tumour/normal white matter of 0.974+/-0.190 (range: 0.768-1.410). On perfusion, the signal intensity-time curve of each tumour showed a characteristic type of curve with a significant increase of the signal intensity above the baseline and a low maximum relative cerebral blood volume ratio (rCVBmax) of 1.43+/-0.64 (0.55-2.62). Due to their higher cellularity, the lack of neoangiogenesis, and the increased permeability of the blood-brain barrier related to the infiltration of blood vessels wall by lymphomatous cells, cerebral lymphoma presents characteristic diffusion and perfusion MRI features that should be useful for diagnosis and patient follow-up.

Clinical relevance of diffusion and perfusion magnetic resonance imaging in assessing intra-axial brain tumors

Advanced magnetic resonance (MR) imaging techniques provide physiologic information that complements the anatomic information available from conventional MR imaging. We evaluated the roles of diffusion and perfusion imaging for the assessment of grade and type of histologically proven intraaxial brain tumors. A total of 28 patients with intraaxial brain tumors underwent conventional MR imaging (T2- and T1-weighted sequences after gadobenate dimeglumine injection), diffusion imaging and T2*-weighted echo-planar perfusion imaging. Examinations were performed on 19 patients during initial diagnosis and on nine patients during follow-up therapy. Determinations of relative cerebral blood volume (rCBV) and apparent diffusion coefficient (ADC) were performed in the solid parts of each tumor, peritumoral region and contralateral white matter. For gliomas, rCBV values were greater in high-grade than in low-grade tumors (3.87+/-1.94 versus 1.30+/-0.42) at the time of initial diagnosis. rCBV values were increased in all recurrent tumors, except in one patient who presented with a combination of recurrent glioblastoma and massive radionecrosis on histology. Low-grade gliomas had low rCBV even in the presence of contrast medium enhancement. Differentiation between high- and low-grade gliomas was not possible using diffusion-weighted images and ADC values alone. In the peritumoral areas of untreated high-grade gliomas and metastases, the mean rCBV values were higher for high-grade gliomas (1.7+/-0.37) than for metastases (0.54+/-0.18) while the mean ADC values were higher for metastases. The rCBV values of four lymphomas were low and the signal intensity-time curves revealed a significant increase in signal intensity after the first pass of gadobenate dimeglumine. Diffusion and perfusion imaging, even with relatively short imaging and data processing times, provide important information for lesion characterization.

[11C]-Methionine PET: dysembryoplastic neuroepithelial tumours compared with other epileptogenic brain neoplasms

BACKGROUND AND OBJECTIVES

Brain tumours responsible for longstanding partial epilepsy are characterised by a high prevalence of dysembryoplastic neuroepithelial tumour (DNT), whose natural evolution is much more benign than that of gliomas. The preoperative diagnosis of DNT, which is not yet feasible on the basis of available clinical and imaging data, would help optimise the therapeutic strategy for this type of tumour. This study tested whether [(11)C]-methionine positron emission tomography (MET-PET) could help to distinguish DNTs from other epileptogenic brain tumours.

METHODS

Prospective study of 27 patients with partial epilepsy of at least six months duration related to a non-rapidly progressing brain tumour on magnetic resonance imaging (MRI). A structured visual analysis, which distinguished between normal, moderately abnormal, or markedly abnormal tumour methionine uptake, as well as various regions of interest and semiquantitative measurements were conducted.

RESULTS

Pathological results showed 11 DNTs (41%), 5 gangliogliomas (18%), and 11 gliomas (41%). MET-PET visual findings significantly differed between the various tumour types (p<0.0002), regardless of gadolinium enhancement on MRI, and were confirmed by semiquantitative analysis (p<0.001 for all calculated ratios). All gliomas and gangliogliomas were associated with moderately or markedly increased tumour methionine uptake, whereas 7/11 DNTs had a normal methionine uptake, including all six located in the mesiotemporal structures. No DNT presented with a marked MET-PET abnormality.

CONCLUSION

Normal MET-PET findings in patient with an epileptogenic and non-rapidly progressing brain tumour are suggestive of DNT, whereas a markedly increased tumour methionine uptake makes this diagnosis unlikely.

Ultrastructural pathology of prion diseases revisited: brain biopsy studies

We report here a detailed ultrastructural comparison of brain biopsies from 13 cases of Creutzfeldt-Jakob disease (CJD) and from one case of fatal familial insomnia (FFI). The latter disease has not heretofore benefited from ultrastructural study. In particular, we searched for tubulovesicular structures (TVS), 35-nm particles regarded as the only disease-specific structures at the level of thin-section electron microscopy. Our material consisted of brain biopsies obtained by open surgery from one FFI case from a new French family, one case of variant CJD (vCJD), nine cases of sporadic CJD (sCJD), two cases of iatrogenic (human growth hormone) CJD and one case of hereditary CJD (Val203Iso). The ultrastructural picture of the cerebral cortex of the FFI patient was virtually indistinguishable from that of CJD. TVS were found, albeit only after prolonged search. Typical spongiform change was observed, consisting of intracellular membrane-bound vacuoles containing secondary chambers (vacuoles within vacuoles) and amorphous material. Neuronal degeneration was widespread: some processes contained degenerating mitochondria and lysosomal electron-dense bodies and these met the criteria for neuroaxonal dystrophy. Other processes contained branching cisterns; still others were filled with electron-dense masses and amorphous vesicles. The overall ultrastructural appearance of variant CJD was similar to that of FFI cerebral cortex, except for a much higher number of cellular processes containing TVS. We detected TVS in the majority of sCJD cases that, in addition to typical spongiform change and robust astrocytic reaction, showed widespread neuritic and synaptic degeneration and autophagic vacuoles. We conclude that TVS are readily found in FFI, vCJD and sCJD and that widespread neuritic degeneration is a part of ultrastructural pathology in prion diseases.

La dystrophie musculaire des ceintures autosomique dominante associée à des troubles de la conduction cardiaque (LGMD1B). Description de 8 nouvelles familles avec mutations du gène LMNA

INTRODUCTION

Limb girdle muscular dystrophy type 1b (LGMD1B), due to LMNA gene mutations, is a relatively rare form of LGMD characterized by proximal muscle involvement associated with heart involvement comprising atrio-ventricular conduction blocks and dilated cardiomyopathy. Its clinical and genetic diagnosis is crucial for cardiac management and genetic counselling. Seven LMNA mutations have been previously reported to be responsible for LGMD1B.

PATIENTS AND METHODS

We describe the neurological and cardiologic features of 14 patients belonging to 8 families in whom we identified 6 different LMNA mutations, 4 of them having never been reported. Results. Eleven patients had an LGMD1B phenotype with scapulohumeral and pelvic-femoral involvement. Thirteen patients had cardiac disease associating conduction defects (12 patients) or arrhythmias (9 patients). Seven patients needed cardiac device (pacemaker or implantable cardiac defibrillator) and two had heart transplantation.

CONCLUSION

This study allowed us to specify the clinical characteristics of this entity and to outline the first phenotype/genotype relations resulting from these observations.

[Analysis of 12 cases of McArdle's disease diagnosed after 30 years]

PURPOSE

McArdle's disease (MAD) or glycogen storage disease type V, usually starts in childhood or adolescence. Generally diagnosis is made before the early adulthood because patients present well defined syndrome and are constrained.

METHOD

We retrospectively investigated all MAD cases diagnosed in the biochemical laboratory from Debrousse Hospital in Lyon, during 40 years (1962-2002). We then selected patients whose diagnosis had been made after 30 years.

RESULTS

Fifteen patients answered our criteria but only 11 files could be analysed. A twelfth patient (service of internal medicine--Royan) supplemented the series. We sought the reasons of a late diagnosis: early age of beginning but few symptoms (7 cases), age of beginning higher than 20 years (5 cases including 3 after 45 years). The principal symptoms were muscular deficit and muscular pains (8 cases) and second wind phenomenon (7 cases). Creatinine phosphokinase level was constantly high. Ischemic effort test when it was carried out was constantly abnormal. Conversely electromyogram was often normal (5 cases). Several biopsies were necessary in a third of the cases to evoke the diagnosis, particularly among the patients with late onset symptoms.

CONCLUSION

Diagnosis of metabolic MAD is generally easy if the interrogation finds inaugural symptoms in childhood or adolescence even if the patient consults very late in the life. The diagnosis can become much more difficult if it begins late in life (atypical symptoms, need for several muscular biopsy).

[Symptomatic carriers of dystrophinopathy with chromosome X inactivation bias]

Several studies have recently highlighted the fact that the clinical involvement in females carrying a mutation in the dystrophin gene could be more frequent than usually thought, suggesting the need of a careful cardiac follow-up. Except for the classical chromosomal rearrangements, it was shown that a bias in the X chromosome inactivation process could be found in some affected females. We report two families illustrating different situations. The propositus of the first family, aged 32, presented with a proximal muscular weakness, increasing for three years, as well as elevated muscular enzymes in blood. Her brother suffered from classical Duchenne muscular dystrophy. Her mother was more severely affected, whereas her sister remained asymptomatic. A duplication of exons 3 to 7 of the dystrophin gene was found in all four patients. The affected carrier from the second family was a sporadic case. She has been suffering from proximal muscular weakness for six years. Muscle biopsy showed a mosaic pattern of the immunostaining using specific antidystrophin antibodies. A stop mutation was found in exon 52. Her ten year-old daughter, carrying the mutation, was asymptomatic. In both families, the inactivation profiles were in accordance with the clinical presentation. We discuss the different mechanisms that may lead to the inactivation bias in these patients, as well as the advantage and limits of using the X chromosome inactivation test as a tool for diagnosis and prognosis purpose in symptomatic carriers for dystrophinopathies.

[Pathology of spastic muscles. Study of 26 patients]

Spastic hypertonia is observed in various central neurological diseases. Pathology of spastic muscle is not well known. Tibial selective microsurgical neurotomy is used for the spastic foot treatment. Twenty-six hemiplegic patients, spastic since more than one year, underwent selective tibial microsurgical neurotomy. Biopsies of soleus, lateral and medial gastrocnemius muscles were performed during surgical treatment, after free patient consent and ethical committee approval. The aim of this study was to describe histopathological lesions of spastic muscles, with histological and histoenzymatic techniques. Histological studies revealed myogenic atrophy, concerning both types of fibers or only type II fibers. They also showed type I (slow fibers) to type II (fast fibers) transformation, in the three studied muscles. These results are similar to those described in the literature.

Interleukin-17 increases the effects of IL-1 beta on muscle cells: arguments for the role of T cells in the pathogenesis of myositis

We studied the production of interleukin (IL)-6 and CCL20/macrophage inflammatory protein-3 alpha (MIP-3 alpha) by human myoblasts and muscle samples in response to IL-17 alone or in combination with IL-1 beta. Both IL-17 and IL-1 beta induced IL-6 production by normal myoblasts and muscle samples. IL-17 had no effect on CCL20 production by myoblasts. Combination of IL-17 and IL-1 beta further increased IL-6 and CCL20 production by muscle samples but not that of CK. IL-17 induced also HLA class I, C-Fos, nuclear factor kappa B (NF-kappa B) and C-Jun expression by myoblasts but not that of HLA class II, CD40, vascular cell adhesion molecule 1 (VCAM-1) and intercellular adhesion molecule 1 (ICAM-1). Finally, immunostaining of dermatomyositis (DM) and polymyositis (PM) muscle biopsies showed IL-17 and CCL20 expression. Our study shows that low levels of cytokines produced by T cells (IL-17) and monocytes (IL-1 beta) can act in combination on skeletal myoblasts and muscle tissue.

[Mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (Melas) associated with a Fahr disease and cerebellar calcifications]

INTRODUCTION

Melas syndrome is a mitochondrial disease which corresponds to the association of mitochondrial encephalopathy, lactic acidosis and stroke-like espisodes.

CASE REPORT

The authors report the case of a 39 year-old woman presenting with hearing loss, seizures, visual field deficit, three stroke-like episodes and calcifications of the basal ganglia and cerebellar dentate nuclei. Melas syndrome was suspected and confirmed by muscle biopsy, showing ragged red fibers and the presence of an A3243G mutation of mitochondrial DNA.

CONCLUSION

This clinical, pathological and radiological observation shows that intracerebral calcifications may involve the dentate nuclei of the cerebellum in the Melas syndrome.

[Solitary plasmacytoma of the sphenoid. A case report]

A rare case of sphenoidal plasmacytoma in a 79 year-old male patient is reported. The diagnosis was preoperatively considered because of associated dysproteinemia and it was histopathologically confirmed on a transphenoidal biopsy specimen. Initial evaluation disclosed no systemic dissemination of the disease and a solitary plasmacytoma was diagnosed. Radiotherapy was delivered with subsequent clinical improvement and significant tumor reduction was illustrated on follow-up imaging studies. Twenty-two months after diagnosis, the patient remains asymptomatic without evidence of transformation to multiple myeloma. Only 7 comparable cases have been reported in the literature. The diagnostic, pathological and nosographic features of sphenoid plasmacytomas are discussed.

[Anterior choroidal artery infarction revealing polyarteritis nodosa]

An 81-year old man presented with a sudden right ataxic hemiparesis. Brain CT scan showed a left anterior choroidal artery territory infarction. Biological signs of inflammation were present without any evidence of infection or neoplasm. The patient's clinical status deteriorated with fever, loss of weight and confusion. Muscle biopsy showed characteristic abnormalities of polyarteritis nodosa (PAN). Oral corticosteroids plus monthly pulse intravenous cyclophosphamide were started. A rapid clinical improvement was observed as well as the resolution of inflammation within one month. Twenty months later, the patient had recovered normal cognitive function and was able to carry out all usual activities. We describe the CNS complications of PAN and the therapeutic options.

Metastasis of clear-cell renal carcinoma to cerebellar hemangioblastoma in von Hippel Lindau disease: rare or not investigated?

A new case of metastatic hypernephroma to cerebellar hemangioblastoma is described in a patient affected by von Hippel-Lindau disease. To our knowledge this is the third reported case of metastasis of renal carcinoma to intracranial hemangioblastoma associated with Von Hippel-Lindau disease. The real frequency of this pathological entity and its management are not well defined.

Polyglucosan bodies and temporal lobe epilepsy: an incidental finding or more?

This study reports on histological findings in the temporal lobe of a 36-year-old woman who underwent a right temporal lobectomy for pharmaco-resistant complex partial seizures. Since surgery, the patient has remained seizure-free. The patient had an established diagnosis of right temporal lobe epilepsy, based on video EEG recordings of seizures, MRI hippocampal atrophy, focal interictal hypometabolism on fluoro-desoxyglucose, hypofixation of Cl1-flumazenil in PET studies, and ictal intracerebral recordings. Biopsies were studied under light- and electron microscopy. Histology showed diffuse distribution of a large number of polyglucosan bodies (PBs) in the whole right temporal lobe white matter. PBs were mostly confined to the perivascular areas and in subpial zones rarely and were observed in the most superficial cortical layers. There was some neuronal loss, especially in opercular zone T , but no other histological lesion was found. Ultrastructurally, PBs were made of filamentous and amorphous material, and were found both in intra-astrocytic processes and in axons. The presence of numerous PBs in the temporal lobe of patients with refractory temporal lobe epilepsy has been reported in 3 patients in the literature. It raises the questions whether this histological abnormality could be related to the epileptogenic process as a cause or as a consequence.

Constrictive bronchiolitis obliterans. Characterisation of fibrogenesis and lysyl oxidase expression patterns

The process leading to irreversible fibrotic constriction of the bronchioles was studied in two cases of bronchiolitis obliterans (BO) after bone marrow transplantation. Because lysyl oxidase (LOX) is the main collagen cross-linking enzyme that might account for irreversible fibrosis, its expression was studied together with expression of extracellular matrix (ECM) proteins. Characteristic types of lesions could be distinguished on the basis of histological and immunohistological criteria. An inflammatory stage was characterised by infiltration restricted to the bronchioles by lymphocytes and dendritic cells. A fibro-inflammatory stage was characterised by the coexistence of a persistent immune cellular lesion pattern with further focal modelling of a sub-epithelial neo-synthesised connective matrix. LOX expression was observed at the tips of intra-luminal fibrotic protrusions, together with tenascin and cellular fibronectin. A fibrotic stage was characterised by dense ECM deposits spreading throughout the peri-bronchiolar connective tissue, resulting in bronchiole obliteration and final disappearance. In contrast to reversible cases of fibrosis, persistence of long-term LOX expression reflecting continuing fibrosing activity might account for the irreversible status of BO. Our two cases illustrated that, at inflammatory and fibro-inflammatory stages, BO may be stabilised by immunosuppressive treatment, while the persistence of LOX expression in the fibrotic stage might correspond to a disease that becomes irreversible and fatal.