Multiple primary intracranial tumors in von Recklinghausen's neurofibromatosis

Extra-axial brain tumors

Extra-axial brain tumors are the most common adult intracranial neoplasms and encompass a broad spectrum of pathologic subtypes. Meningiomas are the most common extra-axial brain tumor (approximately one-third of all intracranial neoplasms) and typically present as slowly growing dural-based masses. Benign meningiomas are very common, and may occasionally be difficult to differentiate from more aggressive subtypes (i.e., atypical or malignant varieties) or other dural-based masses with more aggressive biologic behavior (e.g., hemangiopericytoma or dural-based metastases). Many neoplasms that typically affect the brain parenchyma (intra-axial), such as gliomas, may also present with primary or secondary extra-axial involvement. This chapter provides a general and concise overview of the common types of extra-axial tumors and their typical imaging features.

Triad of Intraspinal Meningioma, Schwannoma, and Ependymoma: Report of an Extremely Rare Case

Mixed tumors composed of schwannoma and meningioma are extremely rare and are usually associated with neurofibromatosis type 2. So far, all the cases reported have involved the cerebellopontine angle. Only 3 reported cases did not have a clear association with neurofibromatosis type 2. We report a mixed tumor comprising schwannoma admixed with meningioma and ependymoma in the cervical spinal cord of a 22-year-old male.

Neoplasms associated with germline and somatic NF1 gene mutations

INTRODUCTION

Neurofibromatosis 1 is a tumor predisposition genetic syndrome with autosomal dominant inheritance and virtually 100% penetrance by the age of 5 years. NF1 results from a loss-of-function mutation in the NF1 gene, resulting in decreased levels of neurofibromin in the cell. Neurofibromin is a negative regulator of various intracellular signaling pathways involved in the cellular proliferation. Although the loss of heterozygosity in the NF1 gene may predispose NF1 patients to certain malignancies, additional genetic alterations are a prerequisite for their development. The precise nature of these additional genetic alterations is not well defined, and genetic testing of all malignancies in NF1 patients becomes an essential component of future research in this subset of patients. In addition to germline NF1 mutations, alteration of the somatic NF1 gene is associated with sporadic malignancies such as adenocarcinoma of the colon, myelodysplastic syndrome, and anaplastic astrocytoma.

MATERIALS AND METHODS

A comprehensive English and non-English language search for all articles pertinent to malignancies associated with NF1 was conducted using PubMed, a search engine provided by the U.S. National Library of Medicine and the National Institutes of Health. Key words searched included the following: "malignancies associated with NF1", "tumors associated with NF1", and "NF1 and malignancies". A comprehensive analysis in terms age and mode of presentation, investigation and therapeutic modalities, and outcome of the published data was performed and compared with similar information on the sporadic cases.

RESULTS

Malignancies in NF1 patients typically occur at an earlier age and, with an exception of optic pathway gliomas, certain types of malignancies carry a poor prognosis compared with their sporadic counterparts. Malignancies are the leading cause of death in NF1 patients, resulting in a 10- to 15-year decreased life expectancy compared with the general population.

CONCLUSIONS

The lack of well-defined screening tests for early detection and the nonspecific clinical presentation contributes to a poorer outcome in malignancies associated with NF1. Small study group size, mixed patient population, and a lack of uniformity in reporting research results make comparison of treatment outcome for this group difficult. An International Consensus Meeting to address and recommend best practices for screening, diagnosis, management, and follow-up of malignancies associated with NF1 is needed.

Coexisting cranial and multiple spinal meningioma in a child-report of a case

Von Ricklinghausen's disease is commonly associated with simultaneous cranial and spinal meningioma but these are not true meningiomas. Craniospinal meningiomas without Von Ricklinghausen's disease are very rare. We report a 13-year-old girl who presented with two episodes of right focal seizure with secondary generalisation of three year's duration, weakness of both lower limbs for 6 months, and retention of urine of three month's duration. MRI brain showed enhancing lesion in the left fronto-parietal region. MRI spine revealed enhancing intradural extramedullary lesion at D(4-5), D(9-10), and L(1-2). The tumours were excised completely in a single stage, first by craniotomy then by multi level laminectomy. On histology the spinal meningioma had predominant meningothiliomatous. We followed up for 6 months and the patient recovered with power grade 4/5 both lower limb.

Microarray analyses reveal regional astrocyte heterogeneity with implications for neurofibromatosis type 1 (NF1)-regulated glial proliferation

Numerous studies have suggested that astrocytes in the central nervous system (CNS) exhibit molecular and functional heterogeneity. In this regard, astroglia from different CNS locations express distinct immune system, and neurotransmitter proteins, have varying levels of gap junction coupling and respond differently to injury. However, the relevance of these differences to human disease is unclear. As brain tumors in children arise in specific CNS locations, we hypothesized that regional astroglial cell heterogeneity might partly underlie the propensity for gliomas to arise in these areas. In this study, we performed high-density RNA microarray profiling on astrocytes from postnatal day 1 optic nerve, cerebellum, brainstem, and neocortex. We showed that astroglia from each region are molecularly distinct, and we were able to develop gene expression patterns that distinguish astroglia, but not neural stem cells, from these different brain regions. We next used these microarray data to determine whether brain tumor suppressor genes were differentially expressed in these distinct populations of astroglia. Interestingly, neurofibromatosis type 1 (NF1) gene expression was decreased at both the RNA and protein levels in neocortical astroglia relative to astroglia from the other brain regions. To determine the functional significance of this finding, we found increased astroglial cell proliferation in optic nerve, brainstem, and cerebellum, but not neocortex, following Nf1 inactivation in vitro and in vivo. These findings provide molecular evidence for CNS astroglial cell heterogeneity, and suggest that differences in tumor suppressor gene expression might contribute to the regional localization of human brain tumors.

Epidemiology of brain tumors

Gliomas account for more than 70% of all brain tumors, and of these, glioblastoma is the most frequent and malignant histologic type (World Health Organization [WHO] grade IV). There is a tendency toward a higher incidence of gliomas in highly developed, industrialized countries. Some reports indicate that Caucasians have a higher incidence than African or Asian populations. With the exception of pilocytic astrocytomas (WHO grade I), the prognosis of glioma patients is still poor. Fewer than 3% of glioblastoma patients are still alive at 5 years after diagnosis, older age being the most significant and consistent prognostic factor of poorer outcome. Gliomas are components of several inherited tumor syndromes, but the prevalence of these syndromes is very low. Many environmental and lifestyle factors including several occupations, environmental carcinogens, and diet have been reported to be associated with an elevated glioma risk, but the only factor unequivocally associated with an increased risk is therapeutic X-irradiation. In particular, children treated with X-irradiation for acute lymphoblastic leukemia show a significantly elevated risk of developing gliomas and primitive neuroectodermal tumors, often within 10 years after therapy. Significant correlation between G:C --> A:T transitions in the TP53 gene and promoter methylation of the O6 -methylguanine-DNA methyltransferase (MGMT) gene in glio-mas have been reported in several studies, suggesting the possible involvement of O6-methylguanine DNA adducts, which may be produced by exogenous or endogenous alkylating agents in the development of gliomas.

Spinal tumors in neurofibromatosis-2: management considerations - a review

Neurofibromatosis Type 2 (NF-2) is a distinct clinical entity, characterized by multiple intracranial and spinal tumors. While bilateral vestibular schwannomas are the pathological hallmark of the disease, significant morbidity in NF-2 is attributable to the presence of both intramedullary and extramedullary spinal tumors. With the advent of MRI as a screening modality, multiple, extensive spinal tumors in the NF-2 population are often seen, which may be clinically quiescent at the time of initial diagnosis. All NF-2 patients should have routine screening with full spinal MRI at the time of diagnosis, regardless of symptoms. Early surgical intervention is indicated in cases where a neurological deficit is attributable to a focal expanding spinal lesion. In asymptomatic patients, the decision to operate is tailored to the individual patient, with the ultimate goal of preserving function. In these cases, surgery should be considered where there is evidence of progressive tumor growth, with attendant risk to the patient of functional deterioration.

Gliomas in neurofibromatosis type 1: a clinicopathologic study of 100 patients

There are few pathologic studies of gliomas in patients with neurofibromatosis type 1. We analyzed clinical and pathologic features of gliomas from 100 neurofibromatosis type 1 patients (57 men; 43 women). The median age at tumor diagnosis was 13 years (range, 4 months to 68 years). Most tumors were typical pilocytic astrocytoma (PA) (49%) or diffusely infiltrating astrocytoma (DA) (27%) that included World Health Organization Grades II (5%), III (15%), and IV (7%); others were designated as low-grade astrocytoma, subtype indeterminate (LGSI; 17%). Two pilomyxoid astrocytomas, 1 desmoplastic infantile ganglioglioma and 1 conventional ganglioglioma, were also identified. The tumors in 24 cases arose in the optic pathways and included PA (n = 14), LGSI (n = 4), DA (n = 4), pilomyxoid astrocytoma (n = 1), and ganglioglioma (n = 1). The prognoses of the PA and LGSI gliomas overall were generally favorable; there were no survival differences between PA and LGSI groups based on site, tumor size, mitotic activity, or MIB-1 labeling index. In the combined PA and LGSI group, age younger than 10 years and gross total resection were associated with an increased overall survival rate (p = 0.047 and 0.002, respectively). Compared with the combined group (PA + LGSI), patients with DA at all sites had decreased overall and recurrence-free survival times (p < 0.001 and p = 0.003, respectively). This study emphasizes the wide histologic spectrum of gliomas that occur in patients with neurofibromatosis type 1. Classic PA and LGSI are the most common, and most have favorable prognoses. By contrast, DAs are more aggressive, similar to those that arise sporadically.

Family history of cancer among children with brain tumors: a critical review

The occurrence of brain tumors in children has been anecdotally associated with an increased cancer incidence among relatives. This study rigorously reviewed the epidemiologic literature regarding family history of cancer in children with brain tumors. Six case-control and 10 cohort studies remained after applying stringent inclusion criteria. Most studies found no significant increase in cancer risk among relatives of childhood brain tumor patients. Those associations that were detected were often of borderline significance or demonstrated wide confidence intervals. There is limited evidence that a family history of cancer is more common among families of childhood brain tumor patients.

Natural history of neurofibromatosis 1-associated optic nerve glioma in mice

Children affected with the inherited tumor predisposition syndrome, neurofibromatosis 1 (NF1), are prone to the development of low-grade astrocytic optic pathway tumors (optic pathway glioma [OPG]). Previously, we developed a model of NF1-associated astrocytoma (GFAPCre; Nf1(flox/mut) mice) in which mice develop optic nerve and chiasm glioma. To define the molecular pathogenesis of OPG, we used this mouse model to study the natural history of OPG formation using immunohistological and radiographic approaches. We observed that whereas astrocyte hyperplasia is present in the optic nerves associated with gross optic nerve thickening at 3 weeks of age, overt neoplastic changes were not seen until 2 months of age. Astrocyte proliferation was maximal between 3 weeks and 2 months of age, suggesting that the most rapid period of growth occurs early. Mouse OPG tumors were detected by magnetic resonance imaging at 2 months of age and exhibited contrast enhancement, as seen in human OPG. In addition, the mouse OPG tumors exhibited expression of proteins associated with astroglial progenitors, including nestin and brain lipid binding protein. Last, we observed neovascularization and microglial cell infiltration by 3 weeks of age before overt neoplastic transformation, suggesting that these cellular changes participate in the early stages of tumor formation.

Epidemiology and etiology of gliomas

Gliomas of astrocytic, oligodendroglial and ependymal origin account for more than 70% of all brain tumors. The most frequent (65%) and most malignant histological type is the glioblastoma. Since the introduction of computerized tomography and magnetic resonance imaging, the incidence rates of brain tumors have been rather stable, with a tendency of higher rates in highly developed, industrialized countries. Some reports indicate that Caucasians have higher incidence than black or Asian populations, but to some extent, this may reflect socio-economic differences and under-ascertainment in some regions, rather than a significant difference in genetic susceptibility. With the exception of pilocytic astrocytomas, the prognosis of glioma patients is still poor. Less than 3% of glioblastoma patients are still alive at 5 years after diagnosis, higher age being the most significant predictor of poor outcome. Brain tumors are a component of several inherited tumor syndromes, but the prevalence of these syndromes is very low. Several occupations, environmental carcinogens, and diet (N-nitroso compounds) have been reported to be associated with an elevated glioma risk, but the only environmental factor unequivocally associated with an increased risk of brain tumors, including gliomas, is therapeutic X-irradiation. In particular, children treated with X-irradiation for acute lymphoblastic leukemia show a significantly elevated risk of developing gliomas and primitive neuroectodermal tumor (PNET), often within 10 years after therapy. TP53 mutations are frequent in low-grade gliomas and secondary glioblastomas derived therefrom. Approximately 60% of mutations are located in the hot spot codons 248 and 273, and the majority of these are G:C-->A:T transitions at CpG sites. TP53 mutations are significantly more frequent in low-grade astrocytomas with promoter methylation of the O(6)-methylguanine-DNA methyltransferase repair gene, suggesting that, in addition to deamination of 5-methylcytosine, exogenous or endogenous alkylation in the O(6) position of guanine may contribute to the formation of these mutations.

Neuroimaging findings in neurofibromatosis type 1 and 2

Neuroimaging, particularly MR imaging, plays an important role in the diagnosis and management of the patient with neurofibromatosis type 1 and 2. These phakomatoses are complex disorders affecting multiple cell types and multiple systems of the body with a wide range of expression. This article summarizes the neuroradiologic central nervous system findings in these neurocutaneous disorders.

Familial gliomas. Analysis of six families with cerebral gliomas and without other inheritable syndromes

Although a familial tendency to develop brain tumors in the absence of well-recognized hereditary disorders is an important issue, it has been rarely reported. Studies of the familial occurrence of gliomas have yielded conflicting results. This phenomenon may be imputable to chance or environmental or hereditary factors. Furthermore, epidemiological and genetic investigations are fundamental to evidence of whether hereditary factors are active in the development of these tumors. We describe a group of six families, in each of which more than one member had glioma, and discuss the probable mechanisms of oncogenesis in familial tumors in light of the pertinent literature.

Genetic abnormalities detected in ependymomas by comparative genomic hybridisation

Using comparative genomic hybridisation, we have analysed genetic imbalance in a series of 86 ependymomas from children and adults. Tumours were derived from intracranial and spinal sites, and classified histologically as classic, anaplastic or myxopapillary. Ependymomas showing a balanced profile were significantly (P<0.0005) more frequent in children than adults. Profiles suggesting intermediate ploidy were common (44% of all tumours), and found more often (P<0.0005) in tumours from adults and the spinal region. Loss of 22q was the most common specific abnormality, occurring in 50% of spinal (medullary) ependymomas and 26% of tumours overall. Genetic profiles combining loss of 22q with other specific abnormalities--gain of 1q, loss of 6q, loss of 10q/10, loss of 13, loss of 14q/14--varied according to site and histology. In particular, we showed that classic ependymomas from within the cranium and spine have distinct genetic profiles. Classic and anaplastic ependymomas with gain of 1q tended to occur in the posterior fossa of children and to behave aggressively. Our extensive data on ependymomas demonstrate significant associations between genetic aberrations and clinicopathological variables, and represent a starting point for further biological and clinical studies.

Cancer incidence in families with multiple glioma patients

Twenty-four Finnish families with 2 or more glioma patients were identified through questionnaires sent to 369 consecutive glioma patients receiving surgery at Tampere University Hospital during 1983-94. To explore whether unusual cancer susceptibility is involved, the cancer risk of 2,664 family members was estimated using population-based data from the Finnish Cancer Registry. Among the total cohort of relatives, 88 cancers were observed during 1953-97. The overall cancer risk among 12 families with juvenile onset gliomas was significantly decreased (standardized incidence ratio [SIR] 0.6, 95% confidence interval [CI]: 0.4-0.9). Among 12 families with adult onset gliomas, the overall cancer risk was equal to that of the reference population (SIR 1.1, 95% CI: 0.8-1.4) whereas the risk of skin melanoma (SIR 4.0, 95% CI: 1.5-8.8) and meningioma (SIR 5.5, 95% CI: 1.1-16) were significantly increased. Several other tumors, including those associated with neurofibromatosis 1 and 2, tuberous sclerosis and Li-Fraumeni and Turcot syndromes were surveyed, but no elevated risks were observed. In conclusion, the presence of meningiomas and skin melanomas in glioma families may indicate a novel association as a cancer susceptibility trait.

Intramedullary and spinal canal tumors in patients with neurofibromatosis 2: MR imaging findings and correlation with genotype

PURPOSE

To determine the appearance of spinal tumors on magnetic resonance (MR) images of patients with neurofibromatosis 2 (NF2), to assess the biologic behavior of these tumors, and to determine the correlation between NF2 germline mutations and these tumors.

MATERIALS AND METHODS

Spinal MR images in 49 patients with NF2 were reviewed retrospectively. Intramedullary and intradural extramedullary tumors were counted, and imaging features and growth patterns of intramedullary tumors were determined. Medical records were reviewed for spinal tumor surgery. Data on spinal tumors and NF2 germline mutations in 37 patients from 19 families were analyzed for genotype-phenotype correlation.

RESULTS

Thirty-one patients (63%) had spinal tumors: Twenty-six (53%) had intramedullary tumors, 27 (55%) had intradural extramedullary tumors, and 22 (45%) had at least one tumor of each type. Three (12%) patients with intramedullary tumors versus 16 (59%) with extramedullary tumors had undergone surgery for the respective types of tumors. Compared with patients with all other types of mutations, a higher percentage of patients with nonsense and frameshift mutations had intramedullary tumors (P <.025); these patients also had higher mean numbers of all tumors (P <.001), intramedullary tumors (P <.001), and nerve sheath tumors (NSTs) (P <.001).

CONCLUSION

In patients with NF2 and spinal tumors, extramedullary tumors (predominantly NSTs) were present in higher numbers and were associated with more surgery than were intramedullary tumors. Our data suggest that the association between nonsense and frameshift mutations and severe NF2 may extend to specific categories of spinal tumors.

Intramedullary ependymomas: clinical presentation, surgical treatment strategies and prognosis

Intramedullary ependymomas are rare tumors but comprise the majority of intramedullary glial neoplasms in the adult. These tumors are benign, slow-growing lesions which are optimally treated with gross-total surgical resection without adjuvant therapy. This objective can be attained safely in a majority, of patients. Post-operative functional outcome is related to pre-operative functional status. Hence, early diagnosis, prior to symptomatic progression, is critical to the successful treatment of these tumors. Adjuvant therapy is indicated for the rare malignant or disseminated tumor or following sub-total resection.

Central nervous system cancers in first-degree relatives and spouses

The increasing incidence of high-grade astrocytomas in the elderly, the associations between these malignancies and environmental factors, and case reports suggesting a familial component to these tumors prompted this study of primary brain tumors in first-degree relatives and spouses. This article describes the findings in 154 patients from 72 consecutive families accrued to the National Familial Brain Tumor Registry from 1991 to 1996. Medical records, pathological slides, and demographic data were reviewed for each identified case. Parents and children were affected in 33 families, siblings in 27, and husbands and wives in 12. The median age of the patients was 50.5 years, 55% were men, and 70% had high-grade astrocytomas. The pattern of tumor occurrence in this population is different from most familial cancers. These tumors did not involve multiple generations or occur at an unusually early age. In addition, the cases tended to cluster in time, with 47% of the familial and 50% of the husband-wife cases occurring within a 5-year span. In families with an affected parent and child, the diagnosis was made in the child before the parent in 45% of the cases. Prognostic factors for these patients appear to be similar to that reported for typical high-grade astrocytomas. This study demonstrates that primary brain tumors can occur in families without a known predisposing hereditary disease. The ages of these patients, the clustering of cases in time, the few affected generations, and the occurrence of brain tumors in spouses suggest that environmental exposures may be important in the etiology of this neoplasm. Although this hypothesis requires further study, it is plausible given the known associations in animals and humans between high-grade astrocytomas and radiation, toxic chemicals, and viruses.

Coexistence of two different intraspinal tumors. Case report and review of the literature

The occurrence of multiple neoplasms in the central nervous system is well documented. In von Recklinghausen's disease, patients frequently present with multiple neurofibromas and/or meningiomas at different sites within the spinal axis. However, the presence of multiple, histologically different spinal tumors in the absence of von Recklinghausen's disease is extremely rare. The authors describe a patient with progressive paraparesis in whom an extradural, malignant lesion and a separate benign, intradural tumor of the thoracic spine were found. The histological diagnosis of the intradural tumor was a pigmented schwannoma. On review of the literature, the authors found nine additional cases of coexisting, histologically different tumors of the spine. The majority of these tumors occurred in the thoracic spine and, not unexpectedly, intradural meningiomas and schwannomas prevailed. Except for the presumed same mesenchymal cell origin of neurinomas and meningiomas, no explanation for the coexisting, different spinal tumors could be determined.

The diagnosis and management of neurofibromatosis 2 in childhood

Neurofibromatosis 2 (NF2) is an autosomal-dominant condition that causes multiple benign nervous system tumors, especially vestibular schwannoma. Although frequently confused with the more common neurofibromatosis 1, NF2 presents a distinct set of diagnostic, genetic, and management issues. The presentation and natural history of NF2 differs in children and adults, with eighth nerve dysfunction often overshadowed by the effects of other tumors on the nervous system. Molecular diagnostics is an important tool for early recognition of NF2, and when performed in the context of appropriate counseling and follow-up, may lead to a better final outcome of the disease. Further research into the molecular genetic etiology of NF2 promises to broaden the possibilities of therapy for this devastating disorder.

Intramedullary spinal cord tumors in neurofibromatosis

Neurofibromatosis (NF) describes the most commonly inherited disorders affecting the nervous system. These autosomal dominant, neurocutaneous syndromes are associated with multiple tumors of the nervous system, including neurofibromas, schwannomas, meningiomas, and intracranial gliomas. Spinal cord involvement in NF is typically from extramedullary growth of spinal nerve root tumors. Intramedullary spinal cord tumors in NF have been reported as scattered, single cases in literature. However, this association has not been clearly defined as have other nervous system neoplasms that are typically linked with NF. We present a series of nine patients with NF with intramedullary spinal cord tumors who were managed at our institution from 1984 to 1994. The patients' ages ranged from 4 to 31 years. There were seven male patients and two female patients. Three patients had NF-1 (von Recklinghausen's), five patients had NF-2, and one patient had NF, type uncertain. There were three cervicomedullary tumors, two cervical tumors, three cervicothoracic tumors, and one thoracic tumor. A histological examination revealed five ependymomas, three astrocytomas, and one intramedullary schwannoma. Two patients with malignant intramedullary spinal ocrd tumors have died with progressive disease. One other patient has required a subsequent operation for recurrent tumor. The other six patients are doing well, and their prognosis is expected to be related to their systemic disease. We conclude that there is a clinical entity of intramedullary spinal cord tumors associated with NF.

Neuropathology and molecular genetics of neurofibromatosis 2 and related tumors

Neurofibromatosis 2 (NF2) is an uncommon, autosomal dominant disorder in which patients are predisposed to neoplastic and dysplastic lesions of Schwann cells (schwannomas and schwannosis), meningeal cells (meningiomas and meningioangiomatosis) and glial cells (gliomas and glial hamartomas). Clinical and genetic criteria that distinguish NF2 from neurofibromatosis 1 have allowed more accurate assignment of specific pathological features to NF2. The NF2 tumor suppressor gene on chromosome 22q12 encodes a widely expressed protein, named merlin, which may link the cytoskeleton and cell membrane. Germline NF2 mutations in NF2 patients and somatic NF2 mutations in sporadic schwannomas and meningiomas have different mutational spectra, but most NF2 alterations result in a truncated, inactivated merlin protein. In NF2 patients, specific mutations do not necessarily correlate with phenotypic severity, although grossly truncating alterations may result in a more severe phenotype. In schwannomas, NF2 mutations are common and may be necessary for tumorigenesis. In meningiomas, NF2 mutations occur more commonly in fibroblastic than meningothelial subtypes, and may cluster in the first half of the gene. In addition, in meningiomas, a second, non-NF2 meningioma locus is probably also involved. Future efforts in NF2 research will be directed toward elucidating the role of merlin in the normal cell and the sequelae of its inactivation in human tumors.

Case report 828: Plexiform neurofibroma of the tibial nerve invading the medial and lateral gastrocnemius muscles and plantaris muscle

A 5-year-old boy presented with a several-year history of swelling of his calf and muscular weakness. MRI demonstrated abnormal signal and diffuse enlargement of the gastrocnemius muscle. Pathological examination revealed plexiform neurofibroma, and the diagnosis of neurofibromatosis was subsequently made. The manifestations of neurofibromatosis and the peripheral nerve sheath tumors encountered in this disease are discussed. Special attention is paid to the MR features of the plexiform neurofibroma which is characteristic of this disorder.

Neurofibromatosis 2: a clinically and genetically heterogeneous disease? Report on 10 sporadic cases

Clinical and genetic data of 10 patients with neurofibromatosis 2 (NF-2) are presented. Interestingly, no family history of neurofibromatosis was detectable in any of them, which indicates that these are sporadic cases of NF-2, most likely due to a new mutational event. According to our own results and the data in the literature, sporadic cases of NF-2 are clinically characterized by a high incidence of multiple meningiomas and spinal tumors in addition to the bilateral occurrence of acoustic neurinomas. The clinical heterogeneity of NF-2 is pointed out and the possible existence of different forms of this disease is discussed.

Familial clustering of malignant astrocytomas

Three of 32 consecutive patients with astrocytomas enrolled in an experimental chemotherapy protocol had at least one first degree relative with an astrocytoma. These patients did not have family members with an excess of malignancies, known exposure to a specific environmental factor, or a recognized neurocutaneous syndrome. In all three families, the illnesses temporally overlapped and the age of the patients affected in the second generation was less than those in the first generation. An estimation of the probability of developing astrocytomas in families with one affected individual strongly suggests a familial effect. Our observations, coupled with other cases reported in the literature, suggest that familial astrocytomas occur more frequently than is currently recognized. Identification and careful study of such families may provide important clues to the etiology of these malignancies.

Experimental model of tumors associated with neurofibromatosis

Four groups of animals, each composed of 22 pregnant Wistar rats, were used in this study. Single intraperitoneal (IP) injections of ethylnitrosourea (ENU) at a dose of 15 mg/kg body weight (BW) were given to the animals of two groups on days 15 and 21 of pregnancy, respectively. The progeny of a third group received by subcutaneous injection (SC) the same dose of ENU, 15 mg/kg BW, on day 1 postnatally. The descendants of the fourth group served as untreated controls. The most striking findings were observed in the progeny of the mothers treated on day 15 of pregnancy, in which group 64 of 180 descendants developed peripheral nervous system (PNS) tumors, 30% of which had plexiform pattern. One hundred fifteen of the 180 descendants developed central nervous system (CNS) gliomas, mainly oligodendrogliomas, and five animals presented with Wilms' tumors. No tumors of these types were observed in the untreated controls. Although descendants of mothers treated on day 21 of pregnancy had the highest number of PNS tumors (130 of 172 animals), only 21% of these tumors were plexiform; CNS gliomas were observed in 78 animals and Wilm's tumors in one animal. The lowest percentage of PNS tumors with plexiform pattern (16%) was found in the group of 157 descendants treated postnatally on day 1, in which 88 animals developed PNS tumors, 76 developed CNS gliomas, and no animals developed Wilms' tumors. The higher percentage of plexiform PNS tumors found in the descendants treated prenatally on day 15 of pregnancy was statistically significant (P less than 0.05) when compared with the percentage found in the group treated postnatally. This significance was also valid for the plexiform tumors that developed selectively from branches of the trigeminal nerves (of the PNS tumors from this location, 48% showed a plexiform pattern), but only in the progeny exposed to ENU on day 15 of pregnancy. This same progeny also had the highest numbers of CNS and Wilms' tumors. Because in humans, plexiform neurofibromas are considered to be the neoplastic markers of neurofibromatosis, and CNS gliomas as well as Wilms' tumors are associated with this disease, it is suggested that exposure to ENU on day 15 of pregnancy, under the experimental conditions described here, may offer a model for investigating tumors associated with neurofibromatosis, as well as aspects of the spontaneous, noninherited forms of this disease.

Mitotic recombination of chromosome 17 in astrocytomas

Allelic combinations at seven loci on human chromosome 17 defined by restriction fragment length polymorphisms were determined in tumor and normal tissues from 35 patients with gliomas. Loss of constitutional heterozygosity at one or more of these loci was observed in 8 of the 24 tumors displaying astrocytic differentiation and in the single primitive neuroectodermal tumor examined. The astrocytomas showing these losses included examples of each adult malignancy grade of the disease, including glioblastoma (malignancy grade IV), and seven of them demonstrated concurrent maintenance of heterozygosity for at least one chromosome 17 locus. Determination of allele dosage together with the genotypic data indicated that the tumor chromosomes 17 were derived by mitotic recombination in 7 of the 9 cases with shared homozygosity of the region 17p11.2-pter in all cases. In contrast, tumors of oligodendrocytic, ependymal, or mixed cellular differentiation did not exhibit loss of alleles at any of the loci examined. These data suggest that the somatic attainment of homozygosity for loci on chromosome 17p is frequently associated with the oncogenesis of central nervous system tumors, particularly those showing solely astrocytic differentiation, and that mitotic recombination mapping is a useful approach towards the subregional localization of a locus whose rearrangement is involved in this disease.

The influence of magnetic resonance tomography on diagnosis and therapy in patients with intracranial manifestation of neurofibromatosis (Recklinghausen disease)

Recent research into the natural course of neurofibromatosis has revealed an outstandingly high proportion of central nervous system malignancies as well as cancers of various other organs. Due to the lack of ionizing radiation, the extraordinary reconstruction in the frontal and parasaggital planes as well as the diagnosis of intracanalicular acoustic neurinomas and intraorbital tumors, magnetic resonance tomography (MRT) is indicated for control of patients with neurofibromatosis.

Multiple brain tumours with von Recklinghausen's disease

Over the past 10 years we have experienced 33 cases of von Recklinghausen's disease, among whom 5 were cases of multiple (3 or more) brain tumours. In the past we have extirpated multiple tumours in a one-stage operation, but the results were poor. Recently, we have done multi-stage operation in two cases thought to require surgical treatment and have obtained satisfactory results. We have discussed the autopsy results of our own case of multiple neurinomas and meningiomas and have reviewed the 44 reported cases of von Recklinghausen's disease in whom the presence of three or more brain tumours had been confirmed at surgery or autopsy.

The malformative central nervous system lesions in the central and peripheral forms of neurofibromatosis. A neuropathological study of 22 cases

The neuropathological features of 22 autopsied cases of NF have been reviewed, with special reference to the malformative and proliferative lesions implicating the intracranial and intraspinal neural structures. Eleven cases represented examples of the central form of the disease, and 11 examples of the peripheral form. The central form is defined by the association and multiplicity of cranial and spinal meningeal, nerve-sheath, and glial neoplasms (astrocytomas and ependymomas). Bilateral acoustic schwannomas are a frequent, but not invariable, component of the disease. Central NF is also characterized by the very frequent incidence (9 out of 11 cases) of distinctive malformative CNS lesions, which included intramedullary and perivascular schwannosis, meningioangiomatosis, discrete ependymal ectopias, atypical glial cell nests in the grey matter, and, less frequently, syringomyelia. Many of these hamartomatous changes were closely associated topographically with florid neoplastic lesions. Five of the 11 cases of peripheral NF showed involvement of the CNS by cellular proliferative changes that included subependymal gliofibrillary nodules in 3 cases (causing aqueduct stenosis in 2, with resulting hydrocephalus in 1); hyperplastic meningioencephalic gliosis involving the pons and the cerebellum in 1 case; and micronodular capillary and arteriolar proliferations typical of the vascular form of NF in 1 case. Whereas some of the glial proliferations are probably hamartomatous in nature, others may represent an abnormal productive neuroglial response to adjacent pathological conditions, such as antecedent cerebral hemorrhage or infarct, known to stimulate a proliferative gliosis. Such a response may exhibit morphological features that are indistinguishable from those of an astrocytoma, including leptomeningeal and perivascular invasion. The incidence of proliferative CNS lesions in both the central and the peripheral form of NF indicates that the spectrum of tissues implicated extends beyond those derived solely from the neural crest.

Skeletal lesions in von Recklinghausen's disease of the head and neck in Nigerian Africans

A study of skeletal lesions in the head and neck region of 20 adult patients with von Recklinghausen's disease, seen in the Surgical Out Patient clinic of Lagos University Teaching Hospital from 1979 to 1985, has been carried out. Among the 20 patients, 13 (65 per cent) had symptoms related to the head and neck while 7 (37 per cent) did not; however, on radiological screening, all of them were observed to have skeletal lesions. The commonest feature was enlarged intervertebral nerve root exit foramina from mesodermal dysplasia, which occurred in 16 (80 per cent) of our patients. Other major findings were erosion of the mandible, 8 (40 per cent); erosion of the wings of the sphenoid, 4 (20 per cent); poor mastoid bone pneumatisation, 3 (15 per cent); erosion of the parietal bone, 3 (15 per cent) and heterotopic bone formation, 1 (5 per cent). Congenital calvarial defects were not detected. In view of the fact that all our patients showed radiologically detectable skeletal lesions of the head and neck, despite absence of symptoms in 35 per cent, it is advisable that all patients with von Recklinghausen's disease should routinely have radiological screening of this region, to detect early lesions.

Long-term follow-up of von Recklinghausen neurofibromatosis. Survival and malignant neoplasms

To document the natural history of von Recklinghausen neurofibromatosis, we followed up a nationwide cohort of 212 affected patients and families identified in Denmark 42 years ago. We obtained follow-up information on 99 percent. Because all 76 probands were identified through hospitals, they may include a disproportionate number of severe cases of neurofibromatosis. To diminish this effect of selection bias, we distinguished between the probands and their affected relatives. In a comparison with the general population, survival rates were significantly impaired in relatives with neurofibromatosis, worse in probands, and worst in female probands. Malignant neoplasms or benign central nervous system tumors occurred in 45 percent of the probands, giving a relative risk of 4.0 (95 percent confidence limits, 2.8 to 5.6) as compared with expected numbers. Multiple primary neoplasms were found in 15 probands, but only 1 relative. Compared with the general population, male relatives with neurofibromatosis had the same rate of neoplasms, whereas female relatives had a nearly twofold higher rate (relative risk, 1.9; 1.1 to 3.1). Nervous system tumors were disproportionately represented. We conclude that patients with severe neurofibromatosis requiring hospitalization often have a poor prognosis, but incidentally diagnosed relatives may have a considerably better outcome.

Synchronous occurrence of glioblastoma multiforme in a husband and wife

Glioblastomas developed within two years of each other in an otherwise unrelated married couple in their fifties. There was a daughter who died of Hodgkin's disease but no other unusual incidence of cancer in either siblings, parents or other children. No clear etiology of risk factors for brain tumor were identified. The development of such conjugal tumors, although apparently rare, raises important etiologic questions.

Otorhinolaryngological manifestations of von Recklinghausen's disease in Nigerians

Otorhinolaryngological manifestations of 13 patients with von Recklinghausen's disease appearing at Lagos University Teaching Hospital over a five-year period have been studied. Among patients with ENT manifestations of the disease, the most common general features exhibited were cutaneous neurofibromas (100 per cent), headache (69.23 per cent) and pruritus (46.15 per cent). But the head and neck findings included external meatal canal stenosis (30.77 per cent), conductive deafness (30.77 per cent), nasal discharge (30.77 per cent), cranial nerve involvement (30.77 per cent) and disfigurement of the soft tissues of the face (30.77 per cent). Involvement of pinna (23.31 per cent), rhinolalia aperta (15.38 per cent), mental retardation (15.38 per cent) and pharyngeal swelling (7.69 per cent) also featured. Clinically detectable bilateral acoustic neurofibromas in adults or astrocytomas in children were not found in this series. Involvement of the frontoparietal bone (7.65 per cent) presented with skull bossing which had to be differentiated from that due to sickle cell disease in the African. There was also a singular case of phrenic nerve involvement. However, malignancy occurred in one (7.69 per cent) of these patients. Thus, it is important always to follow-up these patients closely so as to detect malignant transformation in time.

Plexiform structures in malignant schwannomas after prenatal exposure to ethylnitrosourea

75 Schwann cell tumors were induced in the offspring of Wistar rats which had been treated intraperitoneally with 15 mg/kg b.w. ethylnitrosourea on the 15th day of pregnancy. Plexiform structures characterized by poorly-developed, distorted and bizarre bundles of nerves were seen in 2 of 33 benign tumors, and in 17 of 42 malignant schwannomas. Since when seen in man similar findings are distinctive of neurofibromatosis, it is suggested that this experiment may offer a model for studying non-inherited forms of neurofibromatosis and, more particularly, the malignant changes often associated with this disease.

Cranial computed tomography in the phakomatoses

The authors present the CT findings in their personal series of 77 cases of neurofibromatosis, 34 cases of tuberous sclerosis, and 16 cases of Sturge-Weber disease. These findings are extensively illustrated and compared with those reported in the literature.