Somatic Mutational Landscape of Extracranial Arteriovenous Malformations and Phenotypic Correlations

BACKGROUND

Somatic genetic variants may be the cause of extracranial arteriovenous malformations, but few studies have explored these genetic anomalies, and no genotype-phenotype correlations have been identified.

OBJECTIVES

To characterize the somatic genetic landscape of extracranial arteriovenous malformations and correlate these findings with the phenotypic characteristics of these lesions.

METHODS

This study included twenty-three patients with extracranial arteriovenous malformations that were confirmed clinically and treated by surgical resection, and for whom frozen tissue samples were available. Targeted next-generation sequencing analysis of tissues was performed using a gene panel that included vascular disease-related genes and tumor-related genes.

RESULTS

We identified a pathogenic variant in 18 out of 23 samples (78.3%). Pathogenic variants were mainly located in MAP2K1 (n=7) and KRAS (n=6), and more rarely in BRAF (n=2) and RASA1 (n=3). KRAS variants were significantly (p<0.005) associated with severe extended facial arteriovenous malformations, for which relapse after surgical resection is frequently observed, while MAP2K1 variants were significantly (p<0.005) associated with less severe, limited arteriovenous malformations located on the lips.

CONCLUSIONS

Our study highlights a high prevalence of pathogenic somatic variants, predominantly in MAP2K1 and KRAS, in extracranial arteriovenous malformations. In addition, our study identifies for the first time a correlation between the genotype, clinical severity and angiographic characteristics of extracranial arteriovenous malformations. The RAS/MAPK variants identified in this study are known to be associated with malignant tumors for which targeted therapies have already been developed. Thus, identification of these somatic variants could lead to new therapeutic options to improve the management of patients with extracranial arteriovenous malformations.

Ossifying fibromas of the paranasal sinuses: diagnosis and management

Fibro-osseous benign lesions rarely affect the sinonasal tract and are divided into 3 different entities, namely osteoma, fibrous dysplasia and ossifying fibroma. They share several clinical, radiological and histological similarities, but have different behaviours. Ossifying fibroma, and in particular the "juvenile" histological subtype, may have a locally aggressive evolution and a high risk for recurrence if removal is incomplete. The purpose of the present study is to compare the clinical behaviour of ossifying fibroma with the other benign fibro-osseous lesions; highlight different behaviour between the histological subtypes; compare the advantages, limitations and outcomes of an endoscopic endonasal approach with reports in the literature. We retrospectively reviewed 11 patients treated for sinonasal ossifying fibroma at a tertiary care centre. All patients underwent CT scan, and MRI was performed in cases of cranial base involvement or recurrence. Pre-operative biopsy was performed in cases where it was possible to use an endoscopic approach. One patient underwent pre-operative embolisation with ipsilateral visual loss after the procedure. Depending on its location, removal of the tumour was performed using an endoscopic (n = 7), or an external (n = 3) or combined (n = 1) approach. Histopathologically, 5 patients presented the conventional type, 5 the juvenile psammomatoid variant, which was associated in 1 case with an aneurismal bone cyst, and 1 case presented the trabecular juvenile variant. Three patients affected by the juvenile psammomatoid histological variant presented invasion of the skull base and underwent a subtotal removal that subsequently required, due to the regrowth of the remnant, a transbasal approach. Clinical, radiological and histological findings should all be considered to establish differential diagnosis among fibrous osseous lesions. More studies are necessary to conclude if the localisation and extension of the disease at the time of diagnosis is more important than the histological variant. An endoscopic approach is the first choice in most of cases even if an external open approach may be necessary in selected patients.

Versatile and precise gene-targeting strategies for functional studies in mammalian cell lines

The advent of programmable nucleases such as ZFNs, TALENs and CRISPR/Cas9 has brought the power of genetic manipulation to widely used model systems. In mammalian cells, nuclease-mediated DNA double strand break is mainly repaired through the error-prone non-homologous end-joining (NHEJ) repair pathway, eventually leading to accumulation of small deletions or insertions (indels) that can inactivate gene function. However, due to the variable size of the indels and the polyploid status of many cell lines (e.g., cancer-derived cells), obtaining a knockout usually requires lengthy screening and characterization procedures. Given the more precise type of modifications that can be introduced upon homology-directed repair (HDR), we have developed HDR-based gene-targeting strategies that greatly facilitate the process of knockout generation in cell lines. To generate reversible knockouts (R-KO), a selectable promoter-less STOP cassette is inserted in an intron, interrupting transcription. Loss-of-function can be validated by RT-qPCR and is removable, enabling subsequent restoration of gene function. A variant of the R-KO procedure can be used to introduce point mutations. To generate constitutive knockouts (C-KO), an exon is targeted, which makes use of HDR-based gene disruption together with NHEJ-induced indels on non-HDR targeted allele(s). Hence the C-KO procedure greatly facilitates simultaneous inactivation of multiple alleles. Overall these genome-editing tools offer superior precision and efficiency for functional genetic approaches. We provide detailed protocols guiding in the design of targeting vectors and in the analysis and validation of gene targeting experiments.

The Multiple Facets of PRC2 Alterations in Cancers

Genome sequencing of large cohorts of tumors has revealed that mutations in genes encoding chromatin regulators are frequent in cancer. However, the precise contribution of these mutations to tumor development often remains elusive. Here, we review the current knowledge concerning the alterations of the Polycomb machinery in cancer, with a particular focus on the Polycomb repressive complex 2 (PRC2), a key chromatin modifier involved in the maintenance of transcriptional silencing. A broad variety of alterations can impair PRC2 activity; yet, overall, only one type of alteration is found in a given class of tumor. We discuss the potential impact of the various types of PRC2 alterations on gene expression. We propose that the distinct set of genes regulated by PRC2, depending on tumor etiology, constrain the type of alteration of PRC2 that can fuel tumor development. Beyond this specificity, we propose that PRC2 and, more generally, chromatin regulators act as gatekeepers of transcriptional integrity, a role that often confers a tumor-suppressive function.

Association between EZH2 expression, silencing of tumor suppressors and disease outcome in solid tumors

EZH2, the main catalytic component of the Polycomb Repressive Complex 2 (PRC2) is apparently upregulated in most solid tumors. Furthermore its expression generally associates with poor prognosis. It was proposed that this correlation reflects a causal event, EZH2 mediating the silencing of key tumor suppressor loci. In contrast, we recently showed that EZH2 is dispensable for solid tumor development and that its elevated expression reflects the abnormally high proliferation rate of cancer cells. Here, we investigate the functional association between EZH2 expression and silencing of key tumor suppressor loci and further illustrate the confounding effect of proliferation on EZH2′s association to outcome.

Aspergillus spp. invasive external otitis: favourable outcome with a medical approach

Aspergillus spp. invasive external otitis (IEO) is a rare infection. We performed a seven-year, single-centre retrospective study from 2007 to 2014 including all patients with proven Aspergillus spp. IEO. Twelve patients were identified. All patients had a poorly controlled diabetes mellitus and one underwent solid organ transplant. The most frequently isolated species was Aspergillus flavus (n = 10) and voriconazole was the first-line therapy in all cases, with a median length of treatment of 338.5 days (158-804 days). None of the patients underwent extensive surgery. The clinical outcome was excellent. However, otological sequelae were reported, including hearing impairment (n = 7) and facial palsy (n = 3).

[Prevalence of granulomatous lesions in minor salivary gland biopsy in a case series of 65 patients with tuberculosis]

PURPOSE

The distinction between tuberculosis (TB), a worldwide infectious granulomatosis requiring specific antibiotic therapy, and sarcoidosis, a rare granulomatous disease that may require corticosteroids is not straightforward and may result in diagnostic and therapeutic delay.

METHODS

We prospectively and consecutively evaluated the presence of epithelioid granulomas in minor salivary gland biopsy of 65 consecutive patients with TB.

RESULTS

In our study, 10.8 % of our TB patients had epithelioid granulomas without caseous necrosis identified in their minor salivary gland biopsy, regardless of the location of TB, HIV status and whether or not the sputum examination was positive for tuberculous bacilli.

CONCLUSION

The presence of epithelioid granulomas in minor salivary gland biopsy may not be helpful to the clinician to rule out TB in a patient with suspected sarcoidosis.

Milestones along the road of infection prevention in Egypt

Sequela of infectious diseases include not only morbidity and mortality, but are also associated with chronic illnesses that has long constituted public health problems and huge economic burdens. This review gives a brief idea about important infectious diseases (ID) in Egypt, the main lines taken to combat them, the challenges still existing, and the possible barriers keeping IDs still forming threats to the community. Egypt has the highest prevalence rates of HCV infection worldwide. Significant evidence points towards that the HCV epidemic was initiated and propagated by the anti-schistosomal mass campaigns during the last century. Though the rates of HCV infection are declining, still the decline has not yet met the full expectations. Therefore, infection control programs are gaining more ground all over the country, especially with the growing problem of antimicrobial resistance complicating healthcare-associated infections (HAI) worldwide. Also, mass immnunization of childhood, mycobacterial tuberculosis infections, and avian influenza will be discussed.

Genotypes and phenotypes of 162 families with a glomulin mutation

A decade ago, we identified a novel gene, glomulin (GLMN) in which mutations cause glomuvenous malformations (GVMs). GVMs are bluish-purple cutaneous vascular lesions with characteristic glomus cells in the walls of distended venous channels. The discovery of the genetic basis for GVMs allowed the definition of clinical features to distinguish GVMs from other venous anomalies. The variation in phenotype was also highlighted: from a single punctate blue dot to a large plaque-like lesion. In this study, we screened GLMN in a large cohort of patients to broaden the spectrum of mutations, define their frequency and search for possible genotype-phenotype correlations. Taking into account 6 families published by others, a mutation in GLMN has been found in 162 families. This represents 40 different mutations; the most frequent one being present in almost 45% of them. Expressivity varies largely, without a genotype/phenotype relationship. Among 381 individuals with a mutation, we discovered 37 unaffected carriers, implying a penetrance of 90%. As nonpenetrant individuals may transmit the disease to their descendants, knowledge on the mutational status is needed for appropriate genetic counseling.

[An atypical presentation of Kikuchi-Fujimoto disease]

INTRODUCTION

Histiocytic necrotizing lymphadenitis (Kikuchi-Fujimoto disease) is a rare clinical entity characterized by the association of enlarged lymph nodes in the posterior cervical region and fever. The disease is more frequent in young women.

CASE REPORT

We report a 41-year-old African patient who presented with atypical features of Kikuchi's disease including cutaneous lupus, haemophagocytosis, and lymphocytic meningitis. The ethnic origin and the clinical presentation were initially suggestive of tuberculous meningitis. However, microbiological analyses remained negative, histological findings were suggestive of Kikuchi's disease and HHV6 DNA integration was documented in our patient.

CONCLUSION

Kikuchi's disease should be suspected in an African patient when lymphocytic meningitis is associated with enlarged cervical lymph nodes, hemophagocytosis and HHV6 DNA integration.

[Osteoma cutis presenting as an erythematous and grainy, retroauricular plaque]

BACKGROUND

Authentic bone tissue can be observed in the skin, in both the epidermis and dermis, where it produces cutaneous osteomas. These lesions are classed as either primary or secondary ossifications. Secondary ossifications are the consequence of inflammatory lesions such as acne or injuries while primary ossifications are neither preceded by preexisting lesions nor associated with other lesions.

PATIENTS AND METHODS

A 22-year-old man with no prior history consulted for a grainy, erythematous, telangiectatic retroauricular plaque on the right side. Palpation revealed hard grainy lesions giving a tactile sensation of small stones. Histological analysis showed an ossification in the dermis resulting from mature bone in contact with dilated vessels. A diagnosis of venous malformation with osseous metaplasia was initially proposed, but the patient insisted that no vascular anomaly had preceded the grainy lesions. Further histological analysis demonstrated that the vascular anomalies were restricted to the ossified regions and the final diagnosis was of primary cutaneous osteoma.

DISCUSSION

In our patient, the absence of any endocrine anomalies and of any vascular malformation supported the diagnosis of primary cutaneous osteoma. Certain vascular anomalies such as haemangiomas or venous malformation can lead to bone formation. The coexistence in the dermis of osteomas and dilated vessels initially led us to suspect osteomas secondary to venous malformation. However, the absence of any vascular anomalies preceding the cutaneous osteoma contradicted this diagnosis. In venous malformations, phleboliths are usually seen as a result of calcium deposits on thrombus rather than authentic osteomas. Our patient had no standard primary solitary osteoma of either the nodular or the plaque type, and this case thus constitutes a new original form of primary cutaneous osteoma.

Infrared microspectroscopy analysis of ibuprofen release from drug eluting beads in uterine tissue

Ibuprofen loaded embolization beads (IBU-BB) have been developed to reduce inflammation and pain following uterine artery embolization for the treatment of uterine fibroids. The present work has investigated the elution properties of IBU-BB in situ after embolization with Fourier Transform Infrared Microspectroscopy (FTIRMS). Twelve sheep underwent uterine artery embolization with IBU-BB (485 mM) or control unloaded beads. IBU concentration was determined inside the beads and in the tissue surrounding the beads using FTIRMS of uterine tissue sections sampled 24 h or 1 week after embolization. After 24 h, IBU concentration inside the bead was only 18.6 mM out of the 485 mM initially loaded (p < 0.0001, univariate sign test). The concentration in the tissue around the beads was 8 mM, which is well above the in vitro therapeutic levels (6 microM). After one week the concentration of IBU had decreased to 4.9 mM in the beads (p = 0.0502, Mann Whitney) and no IBU was detected in the surrounding tissue. This work has demonstrated that IBU-BB can provide a sustained release of the anti-inflammatory drug over at least one week. The in vivo elution properties of IBU-BB may be suitable to alleviate pain and inflammation after embolization.

Effect of HO-1 cDNA-liposome complex transfer on erectile signalling of aged rats

This work aimed to assess the efficacy of haeme oxygenase-1 (HO-1) cDNA-liposome complex transfer as a mediator of erectile signalling in aged rats. One hundred and fifty aged white albino rats were equally divided into five groups: controls, rats receiving lipofectamine, rats receiving intracorporeal HO-1 cDNA-lipsome complex, rats receiving HO-1 cDNA-liposome complex plus nitric oxide synthase (NOS) inhibitor, and rats receiving HO-1 cDNA-liposome complex plus HO inhibitor. Six rats were killed from each group after 12, 24 and 48 h, and after1 and 2 weeks. In dissected cavernous tissues, the following were assessed: HO-1 gene expression, Western blot for HO-1, HO enzyme activity, cGMP and histopathology. The results showed that HO-1 cDNA-liposome complex transfer led to a significant increase in cavernous tissue HO-1 protein, HO-1 gene expression, HO enzyme activity and cGMP up to 1 week. NOS inhibition exhibited no effect on HO-1 gene enhancement of cavernous tissue HO enzyme activity or cGMP, whereas inhibition of HO significantly decreased these parameters. Histopathology of cavernous tissue demonstrated a significant dilatation of helicine arteries in HO-1 cDNA-liposome complex treated group after 48 h compared with the controls. It is concluded that HO-1 cDNA-liposome complex transfer augments cavernous tissue cGMP with subsequent sinusoidal relaxation.

Frequency and phenotypes of cutaneous vascular malformations in a consecutive series of 417 patients with familial cerebral cavernous malformations

BACKGROUND

Familial cerebral cavernous malformations (FCCM) are vascular malformations inherited as an autosomal-dominant condition. Three genes (KRIT1/CCM1, MGC4607/CCM2, PDCD10/CCM3) have been identified so far. Extra-neurological manifestations include retinal and cutaneous vascular malformations. The cutaneous vascular malformation, which had been more specifically associated with FCCM, is hyperkeratotic cutaneous capillary venous malformation (HCCVM).

OBJECTIVES

To define the frequency of cutaneous vascular malformations in patients with FCCM, to precise their different phenotypes, and to study the association of each cutaneous vascular malformation subtype with the different three mutated CCM genes.

METHODS

Dermatological inquiry was systematically performed in a large series of consecutive FCCM patients. Cutaneous biopsies were reviewed when available. Cutaneous vascular malformations classification was based on predominant anomalous channels, using the current International Society for the Study of Vascular Anomalies classification. Molecular screening of CCM genes was performed. Results Four hundred seventeen consecutive FCCM patients from 182 unrelated families were included. 38 patients (9%) from 25 different families had cutaneous vascular malformations. In these 38 patients, cutaneous vascular malformations were classified as follows: 13 capillary malformations (CM), 15 HCCVM, 8 venous malformations (VM) and 2 unclassified lesions. All patients (92%), but one with CM had a KRIT1/CCM1 mutation. The last patient had no detectable mutation. All of the 15 patients with HCCVM had a KRIT1/CCM1 mutation; 86.7% of cutaneous vascular malformation patients (33 of 38) had a KRIT1/CCM1 mutation.

CONCLUSION

Cutaneous vascular malformations are seen in 9% of FCCM patients. Three distinct major cutaneous vascular malformations phenotypes were identified: HCCVM (39%), CM (34%) and VM (21%). CCM1 is the most frequently mutated gene in cutaneous vascular malformations-FCCM patients.

Clinical features of early haemarthroses in severely affected adolescent haemophiliacs

Six hundred and ninety bleeds into the knees, ankles and elbows of severe haemophiliacs presenting for treatment within 3 h of the onset of symptoms have been studied with the aim of providing clinical information for the haemophiliac patient or his parent treating early bleeding episodes at home. Patients were resident at a boarding school and documentation and follow-up to complete resolution was possible. Stiffness was a presenting symptom in 61% of elbow bleeds, 49% of knee bleeds and 18% of ankle bleeds. Pain was a presenting feature in 79% of ankle bleeds, 55% of knee bleeds and 42% of elbow bleeds. Tenderness was a common feature of ankle bleeds (85%), less so in elbows (55%) and knees (69%). Swelling was a very common feature at all sites and the mean increases in girth of the knees, elbows and ankles were 1.42 cm, 0.88 cm, and 0.62 cm, respectively. All the knee and elbow bleeds and 85% of the ankle bleeds had demonstrable restriction of movement. There was a direct relationship between the degree of swelling, extent of movement restriction and time taken for complete restoration of function, the mean of which was 3.6 days for elbows, 2.5 for knees and 1.1 for ankles.

The use of an activated factor IX complex (Autoplex) in the management of haemarthroses in haemophiliacs with antibodies to factor VIII

A new activated factor IX product (Autoplex) has been used for the treatment of 18 haemarthroses in three haemophiliac patients with antibodies to factor VIII and a history of high anamnestic response to challenge with factor VIII. Results were evaluated by assessing pain, tenderness, range of movement and girth at 8 and 24 hours. A score of 2 was given for improvement at 8 hours and 1 for improvement at 24 hours. The result was expressed as a percentage of the possible score. Nine episodes treated with less than 35 units of Autoplex/kg had a mean score of 52% and nine episodes treated with more than 35 units/kg had a mean score of 73%. When only the more severe group of bleeds was considered, an even more marked dose related response emerged. When the ratio of the percentage fall in the PT to the percentage fall in the KCCT was plotted against the outcome, a significant correlation emerged (r = 0.43; P = 0.02).

The identification of high risk knee bleeds in adolescents with severe haemophilia A

One hundred and thirty-seven knee bleeds treated with an initial dose of 11-16 units of factor VIII/kg have been reviewed in an attempt to find the predictive factors for bleeds requiring retransfusion. Thirty-two bleeds (23.4%) were retransfused within 48 hours because of extension of bleeding or poor progress. Fifty-nine per cent of bleeds which were retransfused presented with pain and 72% were tender at presentation. These figures contrasted with those for bleeds which were not retransfused of 30% and 45%. The difference in each case is significant. Forty-seven per cent of retransfused bleeds presented with less than 50% of normal movement against 12% who were not retransfused. This difference was also highly significant. It is suggested that knee bleeds presenting with pain, tenderness and/or more than 50% restriction of movement should be considered for higher initial doses of factor VIII.

Endothelial cells in infantile haemangiomas originate from the child and not from the mother (a fluorescence in situ hybridization-based study)

BACKGROUND

Infantile haemangiomas are benign vascular tumours of infancy of unknown origin. Their aetiological relationship to maternal cells has been questioned given that they develop during the neonatal period.

OBJECTIVES

As endothelial cells in the placenta may be of maternal or fetal origin, we questioned whether vascular haemangioma cells originated from fetal or maternal tissue.

METHODS

We aimed to detect, by using fluorescence in situ hybridization, maternal XX cells in the male XY tissue in four specimens of infantile haemangiomas obtained from boys. A sample of a female infantile haemangioma was used as a positive control and a male specimen of melanocytic naevus as a negative control.

RESULTS

In one case of infantile haemangioma, a single XX female - probably maternal - cell was detected in the infantile haemangioma. All the other cells from this male as well as the three other informative specimens were uniformly negative for XX cell detection.

CONCLUSION

Our results support the hypothesis that endothelial cells of infantile haemangiomas appear to derive from the child itself, in accordance with other studies.

Tumeurs et malformations vasculaires, classification anatomopathologique et imagerie

The understanding of vascular anomalies (vascular tumours and vascular malformations) was obscured, for a long time, by confusion and uncertainties in nosology and terminology. The International Society for the Study of Vascular Anomalies (ISSVA) recently adopted a classification scheme, clearly separating vascular tumours (hemangiomas of different types) which result from active cell proliferation, from vascular malformations, which are inborn defects in vascular morphogenesis. These two types of lesions have different clinical behaviour and require different diagnostic and therapeutic strategies. The most frequent vascular tumour is infantile hemangioma. Its clinical aspects and evolution are well-known. New data have been recently obtained concerning the phenotype of tumour cells and its histogenesis. Of the numerous new vascular tumours, which have been recently described, only the congenital hemangiomas, the vascular tumours associated with the Maffucci syndrome and the tumours that may be complicated by a profound thrombocytopenia (Kasabach and Merritt phenomenon) will be considered. Vascular malformations can be classified according to the vessel(s) types they are composed of. A classification table is presented, separating the malformations of vascular trunks from tissular malformations which are more intimately embedded in the surrounding tissues. The different syndromes associated with vascular anomalies take also place in this table. The clinical, imaging and histological aspects of the most frequent malformations (capillary, venous, lymphatic and arteriovenous) are presented. This classification intend to clarify the nosology and terminology of the complex field of vascular tumours and malformation and to offer a common language to the different physicians and specialists contributing, preferably with a interdisciplinary approach, to the diagnosis and treatment of these difficult lesions.

Occlusion of the middle cerebral artery due to synthetic fibers

We report an unusual etiology for a thromboembolic complication. Occlusion of the middle cerebral artery occurred before embolization of an intracranial aneurysm. Attempts to recanalize the artery failed by using both fibrinolytics and IIb/IIIa inhibitors but succeeded with mechanical thrombectomy with a micro-snare. Pathologic analysis of the thrombus showed numerous synthetic fibers that were determined to have originated from unsealed gauze that was used during the procedure.

Facial infantile hemangiopericytoma resembling an arteriovenous malformation

Malignant highly vascularized tumors such as hemangiopericytomas (HPC) may mimic a benign arteriovenous malformation (AVM) which is sometimes still referred to as "angioma". We describe the clinical and radiological findings of a facial hemangiopericytoma in comparison to an AVM in order to avoid misdiagnosis between these two pathologies since evolution and therapeutic management are completely different. Because hemangiopericytomas in children show malignant behavior requiring aggressive management, early and accurate diagnosis is of significant importance for the clinical outcome.