✓ The authors describe a malignant peripheral primitive neuroectodermal tumor (PNET) that originated in the median nerve in an elderly adult. After the diagnosis was made by biopsy, the patient underwent radical local resection with interpositional vein grafting of the brachial artery. The tumor had the typical appearance of a primitive neural tumor with small, round cells forming rosettes. It stained positively for both the Ewing's sarcoma/peripheral PNET antigen (HBA-71) and neuron-specific enolase, confirming its neural origin. Ultrastructural examination revealed dense core granules and suggested neural differentiation of the neoplasm. Cytogenetic analysis suggested a chromosome (11;22) translocation typical of peripheral PNET. Early reports consisted of tumors arising solely in peripheral nerves, but recent series have focused mainly on tumors arising in the soft tissues other than nerves. There are no other cases of true PNET of peripheral nerve in the modern literature that have been fully characterized by immunohistochemical, ultrastructural, and cytogenetic criteria. Although peripheral PNETs occur more commonly in children, this unusual neoplasm should be considered in the differential diagnosis of peripheral nerve neoplasms in adults. Early diagnosis is desirable because of its aggressive nature and poor outcome.
Edward W. Akeyson, Ian E. McCutcheon, Mark A. Pershouse, Peter A. Steck and Gregory N. Fuller
Report of two cases
David Y. Eng, Franco DeMonte, Lawrence Ginsberg, Gregory N. Fuller and Kurt Jaeckle
✓ Central neurocytoma was first described in the literature in 1982 and has been noted to be a benign neuronal tumor usually located in the ventricular system. Of the more than 100 reported cases, only seven recurrences have been reported, all of which have been local. The authors report two cases of recurrent central neurocytoma that disseminated through the ventricular system with seeding to the spine, as evidenced by magnetic resonance images and positive cerebrospinal fluid cytology. The histological appearance of these two tumors was typical for the lesion and lacked evidence of malignant change. Central neurocytoma may not be as benign as previously thought, and the recognition of this more malignant behavior has implications for patient follow up and therapy.
Julie E. York, Rasim H. Berk, Gregory N. Fuller, Jasti S. Rao, Dima Abi-Said, David M. Wildrick and Ziya L. Gokaslan
Object. Primary chondrosarcoma of the spine is extremely rare. During the last 43 years only 21 patients with this disease were registered at The University of Texas M. D. Anderson Cancer Center. The purpose of this study was to examine the demographic characteristics, treatments, and outcomes of this set of patients.
Methods. Medical records for 21 patients were reviewed. Age, sex, race, clinical presentation, tumor histology, tumor location in the spinal column, treatments, surgical details, and response to treatment were recorded. Surgical procedures were categorized as either gross-total resection or subtotal excision of tumor. Neurological function was assessed using Frankel's functional classification. Time to recurrence and survival analyses were performed using the Kaplan—Meier method. The median age of patients was 51 years, with fairly equal gender representation. Eighteen patients underwent at least one surgical procedure for a total of 28 surgical procedures: seven radical resections and 21 subtotal excisions. Radiation therapy was used in conjunction with 10 of the 28 surgical procedures. The median Kaplan—Meier estimate of overall survival for the entire group was 6 years (range 6 months–17 years). Tumors recurred after 18 of the 28 procedures. Kaplan—Meier analysis revealed a statistically significant difference in the per-procedure disease-free interval after gross-total resection relative to subtotal excision (exact log rank 3.39; p = 0.04). The addition of radiation therapy prolonged the median disease-free interval from 16 to 44 months, although this was not statistically significant (exact log rank 2.63; p = 0.16).
Conclusions. Our results suggest that gross-total resection of the chondrosarcoma provides the best chance for prolonging the disease-free interval in patients. Subtotal excision should be avoided whenever possible. Addition of radiation therapy does not appear to lengthen significantly the disease-free interval in this patient population.
Sumeer Lal, Michel Lacroix, Philip Tofilon, Gregory N. Fuller, Raymond Sawaya and Frederick F. Lang
Object. To overcome the problems associated with using stereotactic techniques to establish intracranial xenografts in nude mice and to treat engrafted tumors with intratumoral therapies (such as gene or viral therapies), the authors developed an implantable guide-screw system. In this study, they describe the guide-screw system, its method of implantation, and their experience with establishing xenografts and delivering intratumoral therapy.
Methods. The system consists of a 2.6-mm guide screw with a central 0.5-mm diameter hole that accepts the 26-gauge needle of a Hamilton syringe. The screw is implanted into a small drill hole made 2.5 mm lateral and 1 mm anterior to the bregma. A stylet is used to cap the screw between treatments. Tumor cells or therapeutic agents are injected in a freehand fashion by using a Hamilton syringe and a 26-gauge needle fitted with a cuff to determine the depth of injection. To test this system, guide screws were successfully implanted in 44 (98%) of 45 nude mice. After 1 to 2 weeks of recovery, 38 mice were inoculated with U87MG cells and killed 5 days later. On histological studies in 37 (97%) of these animals, xenografts were evident within the caudate nucleus (mean diameter 2.5 mm). To determine whether injections into the center of an established xenograft could be reproducibly achieved with the guide-screw system, an adenovirus vector containing the β-galactosidase gene was injected 3 days after cell implantation in 15 of the mice. All of these animals demonstrated transduced cells within the tumor. To demonstrate that engrafted animals have a uniform survival time that is indicative of reproducible tumor growth, the survival of six mice was assessed after engraftment with U87MG cells. All six animals died within 28 to 35 days.
Conclusions. The guide-screw system allows a large number of animals to be rapidly and reproducibly engrafted and for intratumoral treatments to be accurately delivered into established xenografts.
Ian E. McCutcheon, Keith E. Friend, Tammy M. Gerdes, Bing-Mei Zhang, David M. Wildrick and Gregory N. Fuller
Object. Although human meningioma cells have been heterotopically implanted in nude mice, introducing these cells into intracranial locations seems more likely to reproduce normal patterns of tumor growth. To provide an orthotopic xenograft model of meningioma, the authors implanted a controlled quantity of meningioma cells at subdural and intracerebral sites in athymic mice.
Methods. Malignant (one tumor), atypical (two tumors), or benign (three tumors) meningiomas were placed into primary cell cultures. Cells (106/10 µl) from these cultures and from an immortalized malignant meningioma cell line, IOMM-Lee, were injected with stereotactic guidance into the frontal white matter or subdural space of athymic mice. Survival curves were plotted for mice receiving tumor cells of each histological type and according to injection site. Other mice were killed at intervals and their heads were sectioned whole. Hematoxylin and eosin staining of these sections revealed the extent of tumor growth.
Conclusions. The median length of survival for mice with malignant, atypical, or benign tumors was 19, 42, or longer than 84 days, respectively. Atypical and malignant tumors were invasive, but did not metastasize extracranially. Malignant tumors uniformly showed leptomeningeal dissemination and those implanted intracerebrally grew locally and spread noncontiguously to the ventricles, choroid plexus, convexities, and skull base. Tumors formed in only 50% of mice injected with benign meningioma cells, whereas injection of more aggressive cells was uniformly successful at tumor production. The three types of human meningiomas grown intracranially in athymic mice maintained their relative positions in the spectrum of malignancy. However, atypical meningiomas became more aggressive after xenografting and acquired malignant features, implying that there had been immune constraint in the original host. Tumor cells injected into brain parenchyma migrated to more optimal environments and grew best there. This model provides insights into the biology of meningiomas and may be useful for testing new therapies.
Daryl R. Fourney, Gregory N. Fuller and Ziya L. Gokaslan
✓ Extradural ependymomas of the sacrococcygeal region are very rare, with most arising from the soft tissues of the presacral area or from the regions dorsal to the sacrum. In even rarer circumstances, the tumor may arise within the sacral canal, likely as a result of ependymal cells of the extradural filum terminale. Because of bone erosion caused by extension of the tumor into the pelvis or dorsal to the sacrum, a truly intraspinal extradural ependymoma in this region has until now never been clearly demonstrated. The authors present a patient with a myxopapillary ependymoma arising from the filum terminale externa in which there was no involvement of the intradural filum or extension outside the sacral canal. A review of the literature is presented, with emphasis on the pathogenesis and clinical management of these rare tumors.
Frederick F. Lang, O. Kenneth Macdonald, Gregory N. Fuller and Franco DeMonte
Object. Primary meningiomas arising outside the intracranial compartment (primary extradural meningiomas [PEMs]) are rare tumors. To develop a better understanding of these tumors and to establish a comprehensive classification scheme for them, the authors analyzed a series of patients treated at the M. D. Anderson Cancer Center (MDACC) and reviewed all cases reported in the English-language literature since the inception of the use of computerized tomography (CT) scanning.
Methods. Clinical records, results of radiographic studies, and histological slides were reviewed for all cases of PEM at MDACC. Demographic features, symptoms, tumor location, histological grade, and patient outcome were assessed in all cases. A comprehensive literature search identified 168 PEMs in 142 patients reported during the CT era. These reports were also analyzed for common features. Tumors for both data sets were classified as purely extracalvarial (Type I), purely calvarial (Type II), and calvarial with extracalvarial extension (Type III). Type II and Type III tumors were further categorized as convexity (C) or skull base (B) lesions.
The incidence of PEMs at MDACC was 1.6%, which was consistent with the rate reported in the literature. In both data sets, the male/female ratio was nearly 1:1. The most common presenting symptom was a gradually expanding mass. The age of patients at diagnosis of PEM was bimodal, peaking during the second decade and during the fifth to seventh decades. In all MDACC cases and in 90% of those reported in the literature the PEMs were located in the head and neck. The majority of tumors originated in the skull (70%).
In the MDACC series and in the literature review, the majority (67% and 89%, respectively) of tumors were histologically benign. Although fewer PEMs were malignant or atypical (33% at MDACC and 11% in the literature), their incidence was higher than that observed for primary intracranial meningiomas. Distant metastasis was not a common feature reported for patients with PEMs (6% in the literature).
Outcome data were available in 96 of the cases culled from the CT-era literature. The combination of the MDACC data and the data obtained from the literature demonstrated that patients with benign Type IIB or Type IIIB lesions were more likely to experience recurrence than patients with benign Type IIC or Type IIIC tumors (26% compared with 0%, p < 0.05). The more aggressive atypical and malignant tumors were associated with a statistically significant higher death rate (29%) relative to benign tumors (4.8% death rate, p < 0.004).
Conclusions. Defining a tumor as a PEM is dependent on the tumor's relation to the dura mater and the extent and direction of its growth. Classification of PEMs as calvarial or extracalvarial and as convexity or skull base lesions correlates well with clinical outcome.
Report of two cases
Fadi Hanbali, Gregory N. Fuller, Norman E. Leeds and Raymond Sawaya
Several types of mass lesions may occur in the third and lateral ventricles. Typically they arise from the lining of the ventricular cavity or from contiguous structures, by extension into the ventricle. The authors describe two patients, each of whom presented with a different rare lesion of the ventricular system. The first was a 53-year-old woman with a history of hypertension who sustained a blunt traumatic injury to the occipital region and subsequently developed a progressively worsening right-sided headache. Radiological examinations over the next 2 years revealed an enlarged right lateral ventricle and, ultimately, a choroid plexus cyst in its anterior and middle third, near the foramen of Monro, which is a rare location for these lesions. The cyst was removed en bloc, and follow-up examinations showed a significant improvement in her headache and a minimal differences in size between right and left ventricles. The authors also describe a 57-year-old man with hypertension, diabetes mellitus, and an old mycardial infarct, who presented to an outside institution with a progressively worsening headache, generalized malaise, and loss of olfactory sensation. Diagnostic imaging revealed a 1.5-cm oval lesion centered in the lamina terminalis region, an open craniotomy was performed, and evaluation of a biopsy sample demonstrated the mass to be a chordoid glioma of the third ventricle, a recently described glioma subtype. Two days after surgery, he suffered a left parietal stroke and an anterior mycardial infarction. After convalescing, he presented to The University of Texas M. D. Anderson Cancer Center for radiotherapy and follow up; 7 months later he was readmitted complaining of headache, short-term memory loss, and worsening confusion and disorientation. Neuroimaging revealed progression of the tumor (now 2 cm in diameter), which was removed by gross-total resection. His headache resolved immediately, and 2 months later his only complaint was of episodes of confusion. Three weeks later he died of a massive myocardial infarction. These two patients represent the sixth case of an adult with a choroid plexus cyst in the anterior lateral ventricle and the 19th case of an adult with a chordoid glioma of the third ventricle, respectively.
Zvi R. Cohen, Eric Marmor, Gregory N. Fuller and Franco Demonte
Olfactory neuroblastoma (ON) is a rare neoplasm arising from the olfactory epithelium and found in the upper nasal cavity. The authors studied the frequency with which ON is misdiagnosed with other tumors of the paranasal sinuses such as neuroendocrine carcinoma (NEC), pituitary adenoma, melanoma, lymphoma, and sinonasal undifferentiated carcinoma (SNUC). Based on the belief that misdiagnosis commonly occurs, they emphasized the importance of establishing the correct diagnosis, because the treatment regimens and prognosis of these tumor types are often significantly different.
Twelve consecutive patients in whom ON was diagnosed were referred to the Department of Neuro-surgery at the M. D. Anderson Cancer Center between January 1998 and March 2000.
Demographic data were collected, physical findings and mode of treatments were documented, and neuroimaging studies were assessed. Pathologists at the authors' institute reviewed the histological specimens. Only in two of 12 patients was the diagnosis of ON confirmed. Lesions in 10 patients were misdiagnosed; there were two cases of mel-anoma, three cases of NEC, three cases of pituitary adenoma, and two cases of SNUC. Eight of 10 patients in whom lesions were misdiagnosed required significant alteration in the initially proposed treatment plan.
Neurosurgeons should be acutely aware of the variety of neoplasms that occur in the paranasal region. The correct diagnosis should be ensured before initiating treatment to provide the optimum therapy and spare the patients from needless and potentially toxic treatment.
Xiang Y. Han, Jeffrey S. Weinberg, Sujit S. Prabhu, Samuel J. Hassenbusch, Gregory N. Fuller, Jeffrey J. Tarrand and Dimitrios P. Kontoyiannis
Object. The cases of five patients with fusobacterial brain abscess are presented. The authors discuss their attempt to determine the pathogenesis.
Methods. The clinical and microbiological features of five cases of fusobacterial brain abscess are reviewed. Isolates of 2031 Fusobacterium spp. and other anaerobes collected (1989–2002) at our institution were analyzed and compared for incidences and isolation sources. The findings were correlated with extensive literature on the subject.
The five patients were men between 45 and 74 years of age. All experienced an insidious onset of the disease and probable hematogenous seeding of the organism(s). One patient had a monomicrobic Fusobacterium necrophorum abscess, whereas the others had polymicrobic F. nucleatum abscesses. Despite surgery and a regimen of antibiotic medications and dexamethasone, three patients experienced a paradoxical deterioration 3 days postoperatively that necessitated reevacuation of the lesion. The evacuants observed at that time contained numerous leukocytes but no microorganisms, suggesting intensified inflammation as the likely cause of deterioration. This explanation is supported by literature that fusobacteria strongly activate neutrophils. An analysis of the 2031 anaerobes from blood, wounds, and abscesses showed the considerable virulence of Fusobacterium spp., which were able to enter and/or sustain themselves in the blood circulation. This pattern was similar to that of Clostridium spp., but different from those of Peptostreptococcus spp., Bacteroides spp., and Prevotella spp., which were less invasive but more abundant.
Conclusions. Some fusobacterial brain abscesses may be associated with a paradoxical postoperative deterioration, which is probably due to intensified inflammation following treatment. The blood-borne dissemination and invasive behavior of fusobacteria likely initiate such a brain abscess, and further seeding of other synergic bacteria leads to a polymicrobic abscess.