C-KIT Expression in Orbital Cavernous Venous Hemangiomas

Orbital (slow flow) cavernous venous hemangiomas (OCVH) are the most common benign orbital tumors in adults. The c-KIT is a tyrosine kinase receptor, which is expressed on several types of cells, is thought to play a key role in tumor pathogenesis. The purpose of this study was to evaluate the presence of the receptor c-KIT in OCVH. Our retrospective study examined 16 orbital cavernous venous hemangiomas from 16 cases operated on between 2006–2016 at Emek Medical Center. The mean tumor size was 18.4 mm. Symptoms appeared between 6 months and 22 years before operation. All specimens were analyzed for the c-KIT receptor through immunohistochemistry. The c-KIT was expressed by the endothelium in all 16 preparates. Staining was strong in two cases, moderate in six, and weak in eight cases, with no statistically significant correlation between staining and tumor size (p = 0.69) or the symptom duration (p = 0.15). We conclude that c-KIT may play an important role in the pathogenesis of OCVH. This pilot study is significant in that tumor-targeted therapy such as Imatinib Mesylate and Sunitinib may have a role in treating surgically complicated cases located in the orbital apex. A large multicenter collaborative study is necessary to examine the role of c-KIT in OCVH.

Familial cerebral cavernous malformation presenting with epilepsy caused by mutation in the CCM2 gene: A case report

RATIONALE

Cerebral cavernous malformation (CCM) of the familial type is caused by abnormalities in the CCM1, CCM2, and CCM3 genes. These 3 proteins forming a complex associate with the maintenance of vascular endothelial cell-cell junctions. Dysfunction of these proteins results in the development of hemangiomas and abnormal intercellular junctions.

PATIENT CONCERNS

We report a 68-year-old man with familial cerebral cavernous malformation with initial presentation as convulsions at an advanced age. Brain magnetic resonance imaging revealed multiple cavernous hemangiomas in the right occipital lobe. The convulsions were considered to be induced by hemorrhage from cavernous hemangioma in the right occipital lobe.

DIAGNOSES

Genetic screening of the CCM1, CCM2, and CCM3 genes revealed a novel mutation in the CCM2 gene (exon4 c: 359 T>A, p: V120D). No abnormalities were found in CCM1 or CCM3. Therefore, we diagnosed the patient with familial CCM caused by a CCM2 mutation.

INTERVENTIONS

This patient was treated with the administration of levetiracetam at a dosage of 1000 mg/day.

OUTCOMES

No seizures have been observed since the antiepileptic drug was administered. We performed brain magnetic resonance imaging (MRI) regularly to follow-up on appearance of new cerebral hemorrhages and cavernous hemangiomas.

LESSONS

This report reviews cases of familial cerebral cavernous malformations caused by abnormalities in the CCM2 gene. This mutation site mediates interactions with CCM1 and CCM3. The mutation occurs in the phosphotyrosine binding (PTB) site, which is considered functionally important to CCM2.

A Case of Multiple Cavernous Hemangiomas with Skin and Central Nervous System Involvement

A 47-year-old woman presented with multiple bluish subcutaneous nodules on the trunk and upper extremities. The histological diagnosis of a subcutaneous nodule was cavernous hemangioma. Multiple cavernous hemangiomas were also found in her cerebrum, cerebellum, and medulla oblongata on magnetic resonance imaging examination. We did not detect any mutations in the two loci of the TIE2 gene that have been reported in familial venous malformations.

Dubin-Johnson syndrome with multiple liver cavernous hemangiomas: report of a familial case

Dubin-Johnson syndrome (DJS) is a rare autosomal recessive inheritance disorder of bilirubin metabolism. Herein we reported a complicated but interesting case which is readily resulted in misdiagnosis or an indefinite diagnosis, and this is the first reported familial case of DJS with multiple liver cavernous hemangiomas. A 49-year-old man was referred to our hospital for jaundice and multiple low-density liver masses. Extensive laboratory investigations showed conjugated hyperbilirubinaemia and positive urine bilirubin. Microscopically, lesions were composed of blood-filled vascular channels of various sizes lined by a single layer of flat endothelial cells supported by fibrous tissue. Coarse brown granules presented in the hepatocytes of the liver lobules locating beside the tumor, particularly in the centrilobular hepatocytes, and the granules showed blue-green with Schmorl's reaction lipofuscin staining. Interestingly, one of the patient's six siblings (female) shared the same condition with him. The relationship between DJS and hemangiomas remains unclear, and it might be contributed to some hereditary factors, or probably occurred simultaneously by chance. It was certified that the true reason for the long-term unclear jaundice was DJS, which was presumed clinically to be caused by bile excretion obstacles associated with the hemangiomas. Liver biopsy and histochemical stain may be helpful to identify the reason of jaundice and avoid misdiagnosis or an indefinite diagnosis.

Vascular disorders associated with thrombohemorrhagic phenomena

This paper has attempted to summarize the more common disease entities which may be accompanied by or may lead to a disorder of hemostasis and/or thrombosis. It is to be emphasized that the vascular component of hemostasis is often overlooked by clinicians caring for individuals with disorders in hemostasis and thrombosis. It is hoped that this brief summary will alert clinicians that the vasculature is equal in importance to the coagulation protein system and to platelets in leading to a hemorrhagic or thrombotic diathesis.

aP2-Cre-mediated expression activation of an oncogenic PLAG1 transgene results in cavernous angiomatosis in mice

The developmentally regulated PLAG1 proto-oncogene has been implicated in the development of various human tumor types, such as pleomorphic salivary gland adenomas, lipoblastomas, hepatoblastomas and AML. In previous studies, we generated two independent PLAG1 transgenic founder strains, PTMS1 and PTMS2, in which PLAG1 could be activated via Cre-mediated excision of a stop cassette. With these founders, PLAG1-induced tumor formation in salivary and mammary glands of mice was studied. To further delineate the oncogenic spectrum of PLAG1 in mice, we induced aP2-Cre-mediated overexpression of PLAG1 in offspring from crossbreeding PTMS1 mice with aP2-Cre transgenic mice. More than 80% of aP2-Cre(+/-)/PLAG1(+/-) (P1-ACre) mice developed a vascular tumor type within one year, which could be classified histopathologically as cavernous angiomatosis. The lesions occurred in various regions of the mouse body but almost exclusively in the immediate surrounding of fat cells. Validation of available PLAG1-induced gene expression profiling data, using targeted tissues, revealed that expression activation of PLAG1 is functional because it leads to elevated levels of PLAG1 target gene transcripts in those tissues, such as for instance those of H19, Dlk1, and Igf-2, similarly as observed in PLAG1-induced salivary and mammary gland tumors. In conclusion, we present the first evidence that links PLAG1 to the molecular pathogenesis of vascular tumorigenesis, known as cavernous angiomatosis, with the possible involvement of Igf signaling and, moreover, further delineate the oncogenic spectrum of PLAG1 in mice, increasing the potential of this transgenic mouse tumor model system for research and therapeutic drug testing.

[Characteristics of endothelial cells derived from human hepatic cavernous hemangioma in vitro]

OBJECTIVE

To investigate the characteristics of endothelial cells derived from human cavernous hemangioma in morphology, phenotypes and functions.

METHODS

Endothelial cells were isolated from human hepatic cavernous hemangioma. The morphological, and phenotypical and functional features of these cells were analyzed by transmission electron microscopy, fluorescence-activated cell sorter, RT-PCR, zymography, and confocal microscopy. Human liver sinusoidal endothelial cells (LSEC) were used as control.

RESULTS

As compared with the LSEC, abnormally expanded endoplasmic reticulums and similarly arranged cytoplasmic vacuoles were found in the endothelial cells derived from hepatic cavernous hemangioma (HCHEC) by transmission electron microscopy. Flow cytometry showed that expression of alphavbeta3 was significantly increased in the HCHEC. The mRNA of vascular endothelial cell growth factor and angiopoietin 1 were more abundant in HCHEC than that in LSEC. Functional analysis indicated that the HCHEC exhibited strong activated angiogenesis capacity and formed abnormal capillary-like structures. HCHEC produced more pro-matrix metalloproteinase 2 (MMP-2) and the activated MMP-2 form as compared with the LSEC. Confocal microscopy revealed that MMP-2 was concentrated in those cytoplasmic granules of the HCHEC and was consistent with the distribution of the expanded endoplasmic reticulums.

CONCLUSION

The endothelial cells derived from human cavernous hemangioma differ from the normal endothelial cells in morphology, phenotypes and functions.

Genetics of cavernous angiomas

Cerebral cavernous malformations (CCM) are vascular malformations that can occur as a sporadic or a familial autosomal dominant disorder. Clinical and cerebral MRI data on large series of patients with a genetic form of the disease are now available. In addition, three CCM genes have been identified: CCM1/KRIT1, CCM2/MGC4607, and CCM3/PDCD10. These recent developments in clinical and molecular genetics have given us useful information about clinical care and genetic counselling and have broadened our understanding of the mechanisms of this disorder.

A splice-site mutation in CCM1/KRIT1 is associated with retinal and cerebral cavernous hemangioma

PURPOSE

To report a case of a unilateral retinal cavernous hemangioma associated with a novel splice-site mutation in CCM1/KRIT1.

METHODS

An 11-year-old girl was noted to have an asymptomatic retinal cavernous hemangioma in the left eye. CCM1/KRIT1 was screened for mutations.

RESULTS

Genetic evaluation of CCM1/KRIT1 revealed a single guanine-to-cytosine transversion in the invariant splice acceptor consensus sequence of intron 8 (c.1146-1G-->C), which is predicted to result in abnormal protein splicing.

CONCLUSIONS

Mutations in CCM1/KRIT1 may be found in asymptomatic patients with retinal cavernous hemangioma.

Karyotypic changes detected by comparative genomic hybridization in a stillborn infant with chorioangioma and liver hemangioma

BACKGROUND

Placental hemangioma (chorioangioma) and congenital hemangioma are relatively common tumors, which on rare occasions may occur together. Very little is known about the pathogenetic mechanisms underlying these lesions.

CASE

Herein we describe a rare case of a stillborn infant with chorioangioma, placental mesenchymal dysplasia, and liver cavernous hemangioma. In addition, we present the findings of the karyotype analysis of these lesions, which was done with the bacterial artificial chromosome arrays using the comparative genomic hybridization method. The chromosomal abnormalities that we found were deletions at 2q13 and 7p21.1 and were common to both placental and liver lesions.

CONCLUSIONS

None of the identified chromosomal aberrations have been previously associated with chorioangiomas or hemangiomas. Important genes that lie in these DNA regions may be implicated in the pathogenesis of congenital hemangiomas and mesenchymal dysplasia.

Clinical impact of CCM mutation detection in familial cavernous angioma

INTRODUCTION AND BACKGROUND

A 3-year-old Bosnian girl with a large symptomatic brainstem and multiple supratentorial cavernous angiomas, who underwent neurosurgical treatment, is presented. As multiple cavernomas are more common in familial cases, genetic analyses and neuroradiological imaging were performed in the patient and her parents to see whether there was any evidence for inheritance. This information is important for genetic counseling and provision of medical care for at-risk relatives. Currently, no recommendation is available on how to manage these cases.

RESULTS

Genetic analyses demonstrated a novel CCM1 frameshift mutation (c.1683_1684insA; p.V562SfsX6) in the child and the asymptomatic 27-year-old mother. Sensitive gradient-echo magnetic resonance imaging of the mother revealed multiple supratentorial lesions, whereas analogous imaging of the father showed no pathological findings.

CONCLUSION

This case exemplifies that seemingly sporadic cases with multiple lesions might well be hereditary and that presymptomatic genetic testing of family members may identify relatives for whom clinical and neuroradiological monitoring is indicated.

Genetics of cerebral cavernous angioma

Cerebral cavernous malformations (CCM) are hamartomatous vascular anomalies characterized by densely packed, grossly enlarged immature capillaries without intervening neural tissue. Depending on their location and size (ranging from a few millimeters to several centimeters), the biologically dynamic lesions become symptomatic during the second to fourth decade of life. Clinical symptoms include recurrent headaches, seizures, intracranial hemorrhage, and stroke. There are sporadic and autosomal dominantly inherited forms of CCM. Causal mutations have been demonstrated in three genes, KRIT1, MGC4607, and PDCD10, but additional genes are likely to be discovered. These genes are therefore thought to play a role in angiogenesis. Their specific modes of actions, their contribution to and their likely penetrance in the genesis of CCM are the subject of current investigations. Genetic counseling is strongly advisable for patients with a positive family history and for seemingly sporadic cases with multiple lesions, and genetic testing should be considered on an individual basis. The identification of a mutation enables precise genetic testing of relatives. Given the 50 % a priori risk of autosomal dominant inheritance, the benefits of genetic testing are twofold: a positive test result in a presymptomatic carrier permits close neuroradiological surveillance and timely neurosurgical intervention; a negative test result relieves the proband of unwarranted anxiety and unnecessary medical supervision.

Identification of two novel mutations and of a novel critical region in the KRIT1 gene

Cerebral cavernous malformations (CCMs) represent a common autosomal dominant disorder that predisposes patients to hemorrhagic strokes and focal neurological signs. Mutations in three genes (KRIT1, MGC4607, and PDCD10) have been associated with CCMs. We investigated the role of two new mutations in the KRIT1 gene in two Italian families affected by CCMs. Whole blood DNA was extracted and the mutations were detected after polymerase chain reaction (PCR), denaturing high-performance liquid chromatography screening, and sequencing of the coding regions of the three CCMs-associated genes. Total RNA was extracted, and the KRIT1 cDNA was sequenced and subsequently subjected to real-time quantitative PCR in order to examine the translational outcome of each genomic mutation. A novel splicing acceptor site deletion of the exon 14 in one family and an intronic nucleotide change close to the exon 19 in the other one were identified, both in the KRIT1 gene. These mutations were proven to alter the correct splicing mechanism, resulting, respectively, in a truncated protein of 432 amino acids and in a protein lacking an internal segment. We report two novel cases of splicing affecting genomic variants, suggesting a careful reanalysis of previously identified splice site variations in KRIT1 to look for their possible causative roles of similar missplicing events and their consequent involvement in the pathogenesis of CCMs. Moreover, our genotype-phenotype functional correlation suggests that the C-terminal portion of the KRIT1 protein is likely to contain a short, previously unrecognized segment necessary for its activity.

Frequency of retinal cavernomas in 60 patients with familial cerebral cavernomas: a clinical and genetic study

OBJECTIVES

To define the frequency of retinal lesions in a large panel of patients with familial cerebral cavernomas and to screen the cerebral cavernous malformation genes in patients with cerebral and retinal lesions.

METHODS

Fundus examination was proposed to each of the index patients of 70 families with cerebral cavernous malformation who have been included in a prospective clinical and neuroradiological follow-up. All of the coding exons of the KRIT1, MGC4607, and PDCD10 genes were screened as previously described.

RESULTS

Of the 70 index patients, 60 were consecutively examined. The 10 remaining patients refused the fundus examination. Three of the 60 examined patients had a retinal cavernoma diagnosis. Three mutations were found: a point mutation within exon 5 of the KRIT1 gene, a large deletion that encompassed exons 1 and 2 of the MGC4607 gene, and a large genomic de novo deletion encompassing the whole PDCD10 gene.

CONCLUSIONS

Retinal cavernoma frequency can be estimated to be about 5% of the patients with familial cerebral cavernomas. Retinal cavernomas are not restricted to KRIT1 mutation carriers but can be observed in patients carrying a mutation in any of the 3 cerebral cavernous malformation genes.

CLINICAL RELEVANCE

Five percent of patients with familial cerebral cavernomas have retinal cavernomas. These lesions are clinically asymptomatic. They can be associated with any of the 3 cerebral cavernous malformation genes.

Cavernous angioma of the internal auditory canal

Cavernous angiomas of the internal auditory canal are rare lesions. The authors present a case of a 29-year-old lady with multiple infratentorial cavernous angiomas, whose sister had previously undergone surgery for a similar supratentorial lesion. She initially presented with an acute brainstem haematoma, secondary to a pontine cavernous angioma. Three years later she developed progressive right-sided sensorineural hearing loss and facial nerve paresis due to an internal auditory canal lesion. This was removed via the translabyrinthine approach and was found to be a cavernous angioma.

This report underlines the multiple and dynamic nature of familial cavernous angiomas, as well as the importance of follow up to determine whether new symptoms are due to the enlargement of known angiomas or the development of new ones. As far as the authors are aware, this is the first report describing a cavernous angioma of the internal auditory canal in the context of familial and multiple infratentorial angiomas.

Chromosomal imbalances in some benign orbital tumours

PURPOSE

To examine benign orbital tumours for chromosomal imbalances.

METHODS

Specimens obtained from orbital tumours were screened for chromosomal imbalances using high resolution comparative genomic hybridization (CGH). The imbalances detected by CGH were confirmed by using fluorescence in situ hybridization (FISH) and loss of heterozygosity (LOH) analysis.

RESULTS

Chromosomal gains or losses were seen in 4/6 pleomorphic adenomas (gains at 8q; losses at 4p, 5p, 8p, 11p and 14q), 2/4 schwannomas (losses at 16p and 22q), and 1/9 cavernous haemangiomas (losses at 13q). Compared to previous studies of pleomorphic adenomas using G-band analysis, chromosomal imbalances were more frequently detected by using CGH. Gains of 8q11-q22 and losses of 4p15-pter, 11p12-p15, and 14q12-q23 in pleomorphic adenomas, losses of 16p12-p13 in schwannomas, and losses of 13q32-qter in cavernous haemangiomas have not been reported previously.

CONCLUSIONS

A range of chromosomal imbalances was detected even within tumours of the same histological subtype. We did not observe common chromosomal gains or losses that were characteristic for orbital presentation of the tumours. The clinical relevance of the abnormalities is uncertain, but they may indicate the position of genes that could play a role in tumour development.

Inactivation of the arylhydrocarbon receptor nuclear translocator (Arnt) suppresses von Hippel-Lindau disease-associated vascular tumors in mice

Patients with germ line mutations in the VHL tumor suppressor gene are predisposed to the development of highly vascularized tumors within multiple tissues. Loss of pVHL results in constitutive activation of the transcription factors HIF-1 and HIF-2, whose relative contributions to the pathogenesis of the VHL phenotype have yet to be defined. In order to examine the role of HIF in von Hippel-Lindau (VHL)-associated vascular tumorigenesis, we utilized Cre-loxP-mediated recombination to inactivate hypoxia-inducible factor-1alpha (Hif-1alpha) and arylhydrocarbon receptor nuclear translocator (Arnt) genes in a VHL mouse model of cavernous liver hemangiomas and polycythemia. Deletion of Hif-1alpha did not affect the development of vascular tumors and polycythemia, nor did it suppress the increased expression of vascular endothelial growth factor (Vegf) and erythropoietin (Epo). In contrast, phosphoglycerokinase (Pgk) expression was substantially decreased, providing evidence for target gene-dependent functional redundancy between different Hif transcription factors. Inactivation of Arnt completely suppressed the development of hemangiomas, polycythemia, and Hif-induced gene expression. Here, we demonstrate genetically that the development of VHL-associated vascular tumors in the liver depends on functional ARNT. Furthermore, we provide evidence that individual HIF transcription factors may play distinct roles in the development of specific VHL disease manifestations.

KRIT1/cerebral cavernous malformation 1 protein localizes to vascular endothelium, astrocytes, and pyramidal cells of the adult human cerebral cortex

OBJECTIVE

Mutations in KRIT1 cause familial cerebral cavernous malformation, an autosomal dominant disorder affecting primarily the central nervous system vasculature. Although recent studies have suggested that Krev-1 interaction trapped 1 (KRIT1) is a microtubule-associated protein that interacts with integrin cytoplasmic domain-associated protein-1alpha, the function of KRIT1 remains elusive.

METHODS

We used Western blotting and immunohistochemistry with specific KRIT1 polyclonal antibodies to investigate KRIT1 protein expression in diverse cerebral and extracerebral tissues.

RESULTS

Immunostaining demonstrates that although KRIT1 is expressed in a broad variety of human organs, it localizes to the vascular endothelium of each, specifically to capillaries and arterioles. KRIT1 antibody fails to stain fenestrated capillaries in the kidney, the liver, or the red pulp of the spleen, where endothelial cells do not to adhere to one another. In contrast, intense staining is observed in the thymus and the white pulp of the spleen, where specialized blood-organ barriers are formed. Other cell types, including various epithelia, cardiac myocytes, and hepatocytes, also stain with KRIT1.

CONCLUSION

Although KRIT1 expression is seen in every endothelium studied, cerebral cavernous malformation lesions are seen almost exclusively in the central nervous system, suggesting that additional cell type(s) contribute to the pathophysiology of cerebral cavernous malformations. Here, we demonstrate that KRIT1 is also present in cells and structures integral to the cerebral angiogenesis and formation of the blood-brain barrier, namely, endothelial cells and astrocytic foot processes, as well as pyramidal neurons in the cerebral cortex.

[New mutations of the 12th exon of CCM1 gene in Chinese patients with intracranial cavernous angiomas]

OBJECTIVE

To study the effect of CCM1 gene mutations in Chinese patients with intracranial cavernous angiomas(ICCA).

METHODS

Twenty-one ICCA patients confirmed by pathology after operations in hospital from June 2002 to Feb.2003 and 15 healthy individuals as contrast were recruited. The peripheral venous blood samples of all the individuals were collected, and then DNA was extracted from the blood samples followed by amplification of exon 12 and some of its intron sequence using PCR. After purification, the PCR products were directly sequenced by ABI PRISM377 sequencing instrument.

RESULTS

Three mutations of CCM1 gene were found in 5 patients and reported firstly. There existed a missense mutation of 1172C-->T in exon 12 in 5 patients, which led the No.391 amino acid of KRIT1 protein, serine, to phenyalanine. There existed a missense mutation of 1160A-->C in one patient, which led the No.387 amino acid, glutamine, to proline. Another mutation was an intronic mutation of IVS12-4C-->T in 4 patients. In contrast no mutations were found.

CONCLUSION

The authors firstly report that mutations of CCM1 gene in exon 12 also exist in Chinese ICCA patients and those mutations are related with the occurring of ICCA.

Hemangiomas hepáticos familiares

Cavernous hemangioma is the most frequent benign hepatic tumor. These tumors are usually small, solitary or multiple, and asymptomatic but they can be large. In the majority of cases, these tumors are sporadic. We describe a family in which six members from three successive generations presented cavernous hepatic hemangiomas. One of the women, who was taking oral contraceptives, presented a giant cavernous hemangioma causing pain in the right hypochondriac region and biochemical abnormalities while the remaining cases were asymptomatic. We found only one study in the literature that reports familial cavernous hepatic hemangioma; a further two studies describe hepatic hemangiomas in members of families with angiomas in other sites. We believe that description of a new family with this disease is of interest. The findings could support autosomal dominant inheritance as the mode of transmission of these tumors, as well as the existence of proliferative factors in these tumors.

Widespread central nervous system cavernous malformations associated with café-au-lait skin lesions. Case report

The simultaneous presence of cavernous malformations in the brain and spinal cord is a very rare finding and is typically associated with familial cavernous malformations. Although they are uncommon, various skin lesions can manifest in patients with familial cavernous malformations. The authors report on a 60-year-old man in whom more than 100 lesions consistent in appearance with cavernous malformations, including several intramedullary spinal cord lesions, were found throughout the neuraxis. This patient also displayed prominent café-au-lait skin lesions, but had no additional signs of neurofibromatosis or other neurocutaneous disorders. Analysis of his DNA revealed a novel mutation in the KRIT1/CCM1 gene, thereby confirming the diagnosis of familial cavernous malformation. The presence of these lesions in every major compartment of this patient's central nervous system underscores their indiscriminate nature and the need to screen throughout the neuraxis in patients in whom familial cavernous malformations are suspected. The findings in this case add to the growing list of skin lesions associated with genetically confirmed familial cavernous malformations. In patients presenting with seizures, focal neurological deficits, or hemorrhagic stroke, the presence of unusual skin lesions should prompt consideration of familial cavernous malformations, and appropriate screening should be performed.

Mutational analysis of 206 families with cavernous malformations

OBJECT

A gene contributing to the autosomal-dominant cerebral cavernous malformation (CCM) phenotype, KRIT1 (an acronym for Krev Interaction Trapped 1), has been identified through linkage analysis and mutation screening. The authors collected blood samples from 68 patients with familial CCM and 138 patients with apparently sporadic CCM as well as from their families, in an effort to characterize the prevalence and spectrum of disease-causing sequence variants in the KRIT1 gene.

METHODS

The authors used single-strand conformational polymorphism analysis to identify genomic variants in KRIT1, which were sequenced to determine the specific mutation. Among 43 Hispanic-American kindreds who immigrated to the southwestern US from northern Mexico, 31 share an identical founder mutation. This Q455X mutation is found in 18 (86%) of 21 persons with a positive family history and in 13 (59%) of 22 persons with apparently sporadic CCM. This mutation was not found among 13 persons with CCM who were recruited from Mexico. These findings establish the key role of a recent founder mutation in Hispanic persons with CCM who live in the US. Although nearly all Hispanic families in the US in which there are multiple CCM cases linked to the CCM1 locus, only 13 of 25 non-Hispanic CCM-carrying families have displayed evidence of linkage to the CCM1 locus. Among these 13 families, the authors identified eight independent mutations in nine kindreds. They identified four additional mutations among 22 familial CCM kindreds with no linkage information, bringing the total number of independent mutations to 12. Inherited KRIT1 mutations were not detected among 103 non-Hispanic persons in whom a family history of CCM was rigorously excluded.

CONCLUSIONS

All mutations were nonsense mutations, frame-shift mutations predicting premature termination, or splice-site mutations located throughout the KRIT1 gene, suggesting that these are genetic loss-of-function mutations. These genetic findings, in conjunction with the clinical phenotype, are consistent with a two-hit model for the occurrence of CCM.

Differential gene expression in human cerebrovascular malformations

OBJECTIVE

We sought to identify genes with differential expression in cerebral cavernous malformations (CCMs), arteriovenous malformations (AVMs), and control superficial temporal arteries (STAs) and to confirm differential expression of genes previously implicated in the pathobiology of these lesions.

METHODS

Total ribonucleic acid was isolated from four CCM, four AVM, and three STA surgical specimens and used to quantify lesion-specific messenger ribonucleic acid expression levels on human gene arrays. Data were analyzed with the use of two separate methodologies: gene discovery and confirmation analysis.

RESULTS

The gene discovery method identified 42 genes that were significantly up-regulated and 36 genes that were significantly down-regulated in CCMs as compared with AVMs and STAs (P = 0.006). Similarly, 48 genes were significantly up-regulated and 59 genes were significantly down-regulated in AVMs as compared with CCMs and STAs (P = 0.006). The confirmation analysis showed significant differential expression (P < 0.05) in 11 of 15 genes (angiogenesis factors, receptors, and structural proteins) that previously had been reported to be expressed differentially in CCMs and AVMs in immunohistochemical analysis.

CONCLUSION

We identify numerous genes that are differentially expressed in CCMs and AVMs and correlate expression with the immunohistochemistry of genes implicated in cerebrovascular malformations. In future efforts, we will aim to confirm candidate genes specifically related to the pathobiology of cerebrovascular malformations and determine their biological systems and mechanistic relevance.

[An intraosseous hemangioma in the perpendicular lamina of the ethmoid bone]

The incidence of intraosseous hemangiomas is very low. Most of them occur in adult females. The mandible,the zygoma,the maxilla, and the frontal and nasal bones are the areas of most frequent localization in the facial region. The intraosseous hemangioma is a benign, slowly growing,bony hard tumor causing facial deformity. It is diagnosed histologically. We report a case of an 18-year-old male with an intraosseous cavernous hemangioma located in the perpendicular lamina of the ethmoid bone. Intraosseous hemangioma often has characteristic signs on a CT scan, with either coarsened trabeculae lying adjacent to the vascular channels or multifocal lytic areas creating a honeycomb pattern. Because of the age of the patient we considered a midline granuloma and a chondrosarcoma. The therapy of choice is surgical excision; radiation is done in exceptional cases only.

Vertebral hemangiomas associated with familial cerebral cavernous malformation: segmental disease expression. Case report

Recently, several groups of authors have described mutations in the Krev interaction-trapped 1 [corrected] (KRIT1) gene in families in whom cerebral cavernous malformations (CCMs) are present. In a number of French kindreds harboring familial CCMs, cutaneous as well as cerebral manifestations of this autosomal-dominant disorder were demonstrated. Involvement of other tissues has been poorly described. The authors present the proband, in an affected family with a previously reported KRIT1 mutation, in whom vertebral hemangiomas in addition to cerebral and cutaneous lesions were found. One of the vertebral lesions was associated with a large cutaneous lesion. This combination of vertebral and overlying cutaneous lesions suggests segmental disease expression as the result of a second hit during development, implying loss of function as the relevant molecular pathogenic mechanism. This case illustrates that tissue involvement outside the nervous system must be considered when treating patients with familial CCMs.

Congenital multiple cavernous angiomas associated with thrombosed arteriovenous malformation of the brain--case report

A 16-year-old girl presented with multiple cerebral cavernous angiomas with calcifications due to repeated hemorrhages and a thrombosed cerebral arteriovenous malformation (AVM). Her 18-year-old elder sister also had multiple cerebral cavernous angiomas associated with calcifications, which suggested presence of repeated previous hemorrhages. Surgical removal via a right occipital craniotomy resulted in a good outcome. The histological diagnosis was thrombosed AVM. Evaluation of congenital vascular anomaly needs to take into consideration the combination of other congenital vascular anomalies and their familial occurrence.

Further study of CD31 protein and messenger ribonucleic acid expression in human cerebral vascular malformations

OBJECTIVE

In a previous study, we documented lower levels of immunoexpression of platelet endothelial cell (EC) adhesion molecule (CD31) in paraffin sections of cerebral cavernous malformations (CCMs), compared with arteriovenous malformations (AVMs) or normal brain tissue. We hypothesized that down-regulation of CD31 in CCMs might represent a distinctive phenotypic feature of ECs in this disease. To confirm this hypothesis, we further examined both protein and messenger ribonucleic acid (mRNA) expression of CD31, using immunohistochemical and in situ hybridization analyses, in fresh-frozen specimens of CCMs, AVMs, and control brain tissue.

METHODS

Fresh-frozen sections of four AVMs, five CCMs, and four control brain tissue specimens obtained from surgical resections were immunohistochemically stained with antibodies to von Willebrand factor and two distinct epitopes of CD31. In two AVMs, four CCMs, and three control brain tissue samples from the aforementioned group, the expression of CD31 mRNA was also examined by using in situ hybridization. Large (>100-microm) and small (<100-microm) vessels were counted and assessed for protein and mRNA expression.

RESULTS

In all tissues, ECs in the majority of vessels were immunopositive for CD31 with two distinct antibodies. CD31 mRNA was expressed in some but not all vessels in AVMs, CCMs, and control brain tissue. There were no statistically significant differences in CD31 protein or mRNA expression in CCMs, AVMs, and control brain tissue.

CONCLUSION

The expression of CD31 in CCMs can be underestimated in paraffin sections. There does not seem to be a unique phenotypic differentiation of CD31 expression in ECs of CCMs or AVMs, compared with control brain tissue.

Prospective follow-up of 33 asymptomatic patients with familial cerebral cavernous malformations

BACKGROUND

Cerebral cavernous malformation (CCM) is one of the most common vascular malformations of the CNS. Familial CCM are increasingly diagnosed, but little is known about their natural history, especially in asymptomatic patients.

OBJECTIVE

To determine the degree of spontaneous evolution of familial CCM in a population of 33 symptom-free patients.

METHODS

During a previous national survey, the authors analyzed the clinical and MRI features of 173 patients from 57 unrelated French families, including 73 asymptomatic subjects. Of these 73 subjects, 33 prospectively underwent two serial clinical and MRI examinations. Cerebral MRI systematically included spin echo and gradient echo sequences. Occurrence of clinical symptoms and MRI changes of CCM, namely, hemorrhage, change in signal intensity, change in size, and appearance of new lesions, were recorded by means of comparison of the first and last MRI examinations.

RESULTS

The 33 patients (234 CCM, mean 7.1 lesions/subject, range 1 to 85 lesions/subject) were followed during a mean period of 2.1 years (range 0.5 to 4.5 years). Two patients became symptomatic: One presented with brainstem hemorrhage and one with partial seizure. Comparison of the two serial MR images found changes in 15 patients (46%): 1) Bleeding occurred in three type II lesions (1.3%) in three patients (9.1%); 2) 30 new lesions appeared in 10 patients (30.3%); 3) change in signal intensity was observed in one lesion (0.4%) in one patient (3%); and 4) increase in size was observed in four lesions (1.7%) in three patients (9.1%).

CONCLUSIONS

This prospective study confirms the dynamic nature of CCM. The appearance of new lesions in 30% of patients has to be retained as a hallmark of the familial condition.

Appearance of new lesions in two nonfamilial cerebral cavernoma patients

Cavernomas are vascular malformations mostly observed in the central nervous system. They occur in sporadic and familial forms. Familial forms are characterized by the presence of multiple lesions, an autosomal dominant pattern of inheritance and possible de novo lesions. We report two sporadic cases whose follow-up showed the appearance of new lesions.

[A case of familial cerebral cavernous angioma and review of Japanese cases]

We present one pedigree of familial cerebral cavernous angioma (FCCA). Case 1 was a 52-year-old male with right hemiplegia. When he was 37 years old, a left occipital lesion was excised and histologically diagnosed as cavernous angioma. MR image showed many cavernous angiomas in the right temporal lobe, the right paraventriclar white matter, the right frontal lobe, the left basal ganglia, and the left parietal lobe. Stereotactic radiosurgery was undertaken for all the lesions. Although the size of each lesion was unchanged, neither hemorrhage nor neurological deterioration were recognized after radiosurgery. Case 2 was a 24-year-old male, a son of the patient in case 1. He has manifested tonic-clonic type epilepsy since the age of 2. MR image showed cavernous angiomas in the pons, the right frontal, and the left intra-Sylvian regions, and many paraventricular cysts with rims indication of previous hemorrhages. Two de novo lesions were observed on subsequent annual MR screening. Surgical excision for the left intra-Sylvian lesion and stereotactic radiosurgery for all lesions were undertaken. Histological diagnosis was cavernous angioma. In the literature, there were 17 pedigrees and 37 cases of FCCA in Japan. The incidence of both multiple lesions and hemorrhage were less than in found in Spanish or French cases. Stereotactic radiosurgery is considered an useful treatment for FCCA, because lesions are multiple and de novo lesions occur.

Familial cavernous hemangioma: An expanding ocular spectrum

OBJECTIVE

To describe the clinical and genetic findings in a family with multiple cases of cavernous hemangiomas.

DESIGN

Investigational clinical and genetic study in which 3 generations of a family consisting of 12 members were screened with magnetic resonance brain imaging, dilated ophthalmoscopic examination, and cutaneous survey coupled with linkage analysis to determine affected individuals and to better define manifestations of this neuro-oculo-cutaneous syndrome.

RESULTS

The proband had multiple cerebral cavernous hemangiomas and a choroidal hemangioma. Her son was found to harbor a retinal cavernous hemangioma. The proband's sister manifested a cerebral cavernous hemangioma, cutaneous hemangiomas, and a presumed choroidal hemangioma; her daughter demonstrated radiological findings suggestive of a cerebral cavernous hemangioma. The father of the proband demonstrated multiple, cutaneous hemangiomas. The remaining family members were free of lesions. The 7q locus could not be excluded as harboring the causative gene.

CONCLUSIONS

This family may have a dominantly inherited neuro-oculo-cutaneous condition of cavernous hemangiomas with variable expressivity. The presence of choroidal hemangiomas in this phacomatosis has not been described previously to our knowledge.

CLINICAL RELEVANCE

The presence of either retinal cavernous or choroidal hemangioma should alert the physician to search for features suggestive of systemic and familial involvement; either lesion may constitute the ocular component of the neuro-oculo-cutaneous phacomatosis, sometimes referred to as cavernoma multiplex. Arch Ophthalmol. 2000;118:969-973

Mutations in KRIT1 in familial cerebral cavernous malformations

OBJECTIVES

The recognition of six unrelated Hispanic-American families in which cerebral cavernous malformations (CCM) segregated as an autosomal dominant trait established a genetic basis for this disease. Linkage analysis subsequently identified locus heterogeneity with disease genes for CCM at chromosomal regions 7q, 7p, and 3q. Recently, mutations in KRIT1, a gene on 7q at the CCM1 locus, were identified in French and Hispanic-American families with CCM. This study confirms the identity the KRIT1 founder mutation in Hispanic-Americans and reports a novel KRIT1 mutation in a Caucasian family.

METHODS

Oligonucleotide primers were designed to allow amplification of genomic DNA sequences from four Hispanic-American families and five non-Hispanic families for all 12 exons of the KRIT1 gene using the polymerase chain reaction (PCR). The amplified DNA was then screened using single strand conformation polymorphism analysis (SSCP) and sequencing. The expression pattern of KRIT1 was analyzed by Northern blotting.

RESULTS

Analysis of the KRIT1 gene revealed a point mutation in exon 6 that predicts the substitution of a premature termination codon for glutamine at codon 248 in all four Hispanic-American families, confirming previous findings. SSCP analysis and sequencing revealed an 11 base pair duplication in exon 7 leading to a premature termination codon in one Caucasian family. Northern analysis demonstrated widespread expression of this gene, however, the highest level of expression was in the brain.

CONCLUSION

The common KRIT1 mutation causing the majority of CCM in Hispanic-Americans has been identified and independently confirmed, allowing efficient presymptomatic molecular diagnosis. In keeping with prior results, both newly identified mutations create a premature termination codon and are predicted to initiate degradation of the mutant mRNA through the nonsense-mediated mRNA decay pathway. These data strongly suggest loss of function as the relevant patho-genetic mechanism.

Truncating mutations in CCM1, encoding KRIT1, cause hereditary cavernous angiomas

Cavernous angiomas are vascular malformations mostly located in the central nervous system and characterized by enlarged capillary cavities without intervening brain parenchyma. Clinical symptoms include seizures, haemorrhage and focal neurological deficits. Cavernous angiomas prevalence is close to 0.5% in the general population. They may be inherited as an autosomal dominant condition in as much as 50% of cases. Cerebral cavernous malformations (CCM) loci were previously identified on 7q, 7p and 3q (refs 4,5). A strong founder effect was observed in the Hispano-American population, all families being linked to CCM1 on 7q (refs 4,7). CCM1 locus assignment was refined to a 4-cM interval bracketed by D7S2410 and D7S689 (ref. 8). Here we report a physical and transcriptional map of this interval and that CCM1, a gene whose protein product, KRIT1, interacts with RAP1A (also known as KREV1; ref. 9), a member of the RAS family of GTPases, is mutated in CCM1 families. Our data suggest the involvement of the RAP1A signal transduction pathway in vasculogenesis or angiogenesis.

The natural history of cavernous malformations

This article reviews general information about cavernous malformations, including histology, radiology, epidemiology, and symptomatology. Rates of hemorrhage as reported in the literature are presented. Familial cavernous malformations and their genetic basis are discussed. Finally, the variations in the biological behavior of cavernous malformations in different regions of the central nervous system are discussed and outcomes are assessed.

Patients with spinal cord cavernous malformations are at an increased risk for multiple neuraxis cavernous malformations

OBJECTIVE

To determine the prevalence of multiple neuraxis cavernous malformations in patients who initially presented with intramedullary spinal cord (IMSC) cavernous malformations without knowledge of cavernous malformations elsewhere in the neuraxis.

METHODS

Hospital records and radiographic files were analyzed for 17 patients who subsequently underwent surgical resection of an IMSC cavernous malformation (histologically proven) and also underwent brain magnetic resonance imaging studies. These 17 patients represented a subset of 32 patients who underwent surgical resection of an IMSC cavernous malformation during the same period.

RESULTS

Of 17 patients, 8 (47%) harbored multiple cavernous malformations. This group was composed of five women and three men (mean age, 35.9 yr). There were four Caucasian and four Hispanic patients.

CONCLUSION

The prevalence of multiple cavernous malformations in the neuraxis seems to be increased in patients who harbor IMSC cavernous malformations. This finding has important implications for the evaluation and management of these patients and, in some cases, their family members.

Genetic heterogeneity and absence of founder effect in a series of 36 French cerebral cavernous angiomas families

Cerebral cavernous angiomas malformations (CCM) can be inherited as an autosomal dominant condition. CCM1, a yet unidentified gene mapping on 7q21-q22, was shown to be involved in all CCM Hispano-American families, with a strong founder effect. Genetic heterogeneity in non Hispano-American families was established in two families. We conducted a genetic linkage analysis on 36 French CCM families using eight microsatellite markers mapping within the CCM1 interval. Admixture analysis showed that 65% of these families were linked to the CCM1 locus. Haplotypes analysis of CCM1-linked families did not show any evidence for a strong founder effect.

An association between autosomal dominant cerebral cavernomas and a distinctive hyperkeratotic cutaneous vascular malformation in 4 families

Cerebral cavernomas (CCMs) are vascular malformations that may be inherited as an autosomal dominant condition for which a gene, CCM1, was mapped to chromosome 7. Poorly defined cutaneous malformations were sometimes described in association with CCMs. During a national survey, 57 French CCM families were studied. Co-occurrence of CCMs and a distinctive cutaneous vascular malformation was observed in 4 families. Ten individuals belonging to these families showed similar hyperkeratotic cutaneous capillary venous malformations (HCCVMs). In 3 families, the histology showed orthokeratosis and hyperkeratosis as well as dilated capillaries in the dermis extending to the hypodermis and confirmed the diagnosis of HCCVM. Genetic analysis strongly supports linkage of these families to the CCM1 locus on chromosome 7. The HCCVM seems to be a peculiar cutaneous vascular malformation associated with CCMs. These data strongly suggest that HCCVMs and CCMs in these families are due to the same genetic abnormality.

[The study on the role of apoptosis suppressive gene bcl-2 in the pathogenesis of hemangioma]

OBJECTIVE

To elucidate the relationship between bcl-2 and hemangioma.

METHODS

We investigated the expression of bcl-2 in 38 samples of hemangioma (19 cases of capillary hemangioma, 10 cases of cavernous hemangioma, 9 cases of racemose hemangioma) and 6 samples of normal skin by immunohistochemical SP method.

RESULTS

The results showed that the expression of bcl-2 was higher in cavernous and racemose hemangioma than in the controls, the expression of bcl-2 was lower in capillary hemangioma than in the controls. The differences were statistically significant.

CONCLUSION

It can be deduced from the results that there is an intimate relationship between bcl-2 and the growth of cavernous and racemose hemangioma, and the lower expression of bcl-2 in capillary hemangioma shows that capillary hemangioma may disappear naturally.