Distinguishing recurrent tumor and radiation necrosis with positron emission tomography versus stereotactic biopsy

With the recent approval of reimbursement for positron emission tomography (PET), it has become important to clarify the utility of this diagnostic study. We evaluated the utility of PET to distinguish radiation necrosis from recurrent tumor in a retrospective review of patients with primary glial neoplasms. Fifteen patients had preoperative contrast-enhanced MRI and PET images followed by stereotactic biopsy or craniotomy and histological confirmation. The sensitivity of PET was 43% (6/14) and the specificity was 100% (1/1). We examined the sensitivity of PET as a function of volumetric contrast enhancement on MRI. Eighty percent of true-positive PET studies occurred with volume enhancement greater than 10 cm(3). Seventy-five percent of false negatives occurred with volume enhancement less than 6 cm(3). Given the clinical significance of distinguishing tumor progression from radiation necrosis, we believe that PET is insufficient to resolve radiation necrosis versus tumor progression.     

Associations among magnetic resonance spectroscopy, apparent diffusion coefficients, and image-guided histopathology with special attention to radiation necrosis

OBJECTIVE: In patients with malignant glioma previously treated with surgery, radiation, and chemotherapy, clinical and radiographic signs of recurrent disease often require differentiation between radiation necrosis and recurrent tumor. Published work suggests that although magnetic resonance spectroscopy (MRS) can reliably differentiate pure tumor, pure necrosis, and spectroscopically normal tissues, it may not be particularly helpful because most patients have mixed histological findings comprised of necrosis and tumor. To improve our clinical ability to discriminate among these histological entities, we have analyzed MRS in conjunction with apparent diffusion coefficient (ADC) sequences derived from magnetic resonance imaging. METHODS: In 18 patients, spectroscopic and diffusion-weighted images were obtained before surgery for suspected recurrent neoplastic disease. Spectral data for pure tumor, pure necrosis, and mixed tumor and necrosis were derived from 65 spectroscopic observations in patients with previously treated gliomas (n = 16) and metastatic tumors (n = 2). Spectral data for choline (Cho), N-acetylaspartate (NAA), creatine (Cr), and lipid-lactate were analyzed separately and in conjunction with ADCs in all patients (15 observations of pure tumor, 33 observations of pure necrosis, and 13 observations of mixed tumor and necrosis). Histological specimens were obtained stereotactically at the time of surgery (<48 h after image acquisition) for recurrent disease and digitally co-registered with MRS data. RESULTS: ADC values for pure tumor, pure necrosis, and mixed tumor and necrosis were 1.30, 1.60, and 1.42, respectively. Cho/NAA less than 0.20, NAA/normal Cr greater than 1.56, and NAA/Cho greater than 1.32 increase the odds that a tissue biopsy will be pure necrosis versus mixed tumor and necrosis. Although various values of all MRS ratios analyzed may provide positive correlations for histopathological differentiation of tissue between that of pure tumor and that of pure necrosis, the addition of ADC values to only NAA/Cho and NAA/normal Cr increases the odds of correct differentiation between pure tumor and pure necrosis. The addition of ADC values does not provide additional information beyond that of MRS in distinguishing specimens of mixed tumor and necrosis from either pure tumor or pure necrosis. CONCLUSION: It has been demonstrated that MRS ratio analysis may allow for the clinical discrimination between specimens of pure tumor and pure necrosis, and the addition of ADC data into this analysis may enhance this specific differentiation. However, although a trend toward correlation between ADC values and the various histopathological features was noted, the direct addition of ADC data does not seem to allow further discrimination, beyond that provided by MRS, among specimens of mixed tumor and necrosis and either pure tumor or pure necrosis.     

Enhanced accuracy in differential diagnosis of radiation necrosis by positron emission tomography-magnetic resonance imaging coregistration: technical case report

OBJECTIVE AND IMPORTANCE: To demonstrate the usefulness of positron emission tomography-magnetic resonance imaging (MRI) coregistration for differentiation of radiation necrosis and recurrent tumor in stereotactic planning. CLINICAL PRESENTATION: T1-weighted MRI scans of a 43-year-old woman revealed a contrast-enhancing lesion 4 years after open removal of a recurrent, right parieto-occipital Grade II oligodendroglioma and subsequent external radiation therapy. The suspected contrast-enhancing lesion revealed only moderate tracer uptake (1.3 times the uptake in the contralateral normal cortex) in a coregistered [11C]methionine positron emission tomographic scan. Approximately 15 mm posterior and mesial to the center of the contrast-enhancing lesion, however, an area of higher tracer uptake was found (1.8 times that of the contralateral normal cortex), which exhibited only very minor contrast enhancement on MRI. TECHNIQUE: The coregistered images were used for planning stereotactic serial biopsies, from the contrast-enhancing lesion as well as from the area with higher methionine uptake. Histological examination demonstrated that the contrast-enhancing lesion with low methionine uptake was necrotic tissue, and the nonenhancing area with high methionine uptake was recurrent tumor. CONCLUSION: High-resolution positron emission tomography and modern coregistration techniques allow differentiation of contrast enhancement and methionine uptake in irradiated brain tissue within small areas. High methionine uptake is typical for recurrent tumor tissue and can be differentiated from minor tracer accumulation resulting from disruption of the blood-brain barrier or macrophage activity within the necrotic area.     

Frontal atypical teratoid/rhabdoid tumor evaluated by single-photon emission computerized tomography and positron emission tomography

A case of frontal atypical teratoid/rhabdoid tumor (AT/RT) was presented in the findings of single-photon emission computerized tomography (SPECT) using 201Tl-chloride (Tl) and 123I-metaiodobenzylguanidine (MIBG), and positron emission tomography using 18F-fluorodeoxyglucose (FDG) and (11C-methyl)-L-methionine (Met). A 16-year-old female had an episode of Jacksonian seizures one month prior to admission. CT scans showed an isodensity mass with heterogeneous enhancement in the left frontal lobe. MR images revealed a tumor with solid and cystic components and perifocal edema. SPECT demonstrated intense accumulation of Tl and MIBG in the enhancing lesion 15 min and 30 min after intravenous injection of tracers, respectively. The 6-hr delayed SPECT showed no retention of MIBG in the enhancing lesion. FDG-PET and Met-PET revealed high uptake of tracers in the enhancing lesion. Met did not accumulate in the frontal white matter, which appeared hyperintense on T2-weighted MR images. The patient underwent an uneventful extirpation of the solid mass, where Met had accumulated. Microscopically, the solid tumor contained rhabdoid cells, spindle-shaped cells resembling mesenchymal cells, and nests of small cells. The tumor cells were immunoreactive for vimentin, cytokeratin, and epithelial membrane antigen. The MIB-1 labeling index was 25%. The histological diagnosis was AT/RT. Postoperative course was uneventful. A dose of 32.4 Gy was administrated to the whole brain and a boost of 27.8 Gy to the T2-hyperintensity lesion. Five months after the radiotherapy, MRI showed neither abnormal enhancing lesions nor the T2-hyperintensity lesion. Multifarious studies using SPECT and PET are useful for differential diagnosis and for choosing optimal therapeutic strategy for this type of tumor.     

Radionecrosis of malignant glioma and cerebral metastasis: A diagnostic challenge in MRI

Detecting a new area of contrast-enhancement at MRI after irradiation of malignant brain tumor arises the problem of differential diagnosis between tumor recurrence and radiation necrosis induced by the treatment. The challenge for imaging is to distinguish the two diagnoses given: the prognostic and therapeutic issues. Various criteria have been proposed in the literature based on morphological, functional or metabolic MRI. The purpose of this study was to perform an analysis of these tools to identify MRI best criteria to differentiate radiation necrosis lesions from malignant gliomas and brain metastases recurrence. For gliomas, the morphology of the contrast-enhancement cannot guide the diagnosis and the use of perfusion techniques and spectroscopy (multivoxels if possible) are necessary. In the follow-up of metastasis, a transient increase and moderate lesion volume is possible with a good prognosis. Morphological characteristics (volume ratio T2/T1Gd) and perfusion analysis provide valuable tools for approaching the diagnosis of radionecrosis.     

Differentiation of the radiation-induced necrosis and tumor recurrence after gamma knife radiosurgery for brain metastases: importance of multi-voxel proton MRS.

Comparative analysis of the diagnostic accuracy of FDG PET, single-voxel, and multi-voxel proton MRS for differentiation between radiation-induced necrosis and tumor recurrence was done in 9 patients with brain metastases treated by gamma knife radiosurgery. In all cases enlargement of the lesion and increase of the perilesional edema were demonstrated by MRI on average 10.6+/-2.6 months after initial treatment. Radiation-induced necrosis was identified in 5 patients (histologically in 2, clinically in 3). In one of these a false positive result of FDG PET was observed, whereas data of proton MRS were always correct. The diagnosis of tumor recurrence was established in 4 patients (histologically in 3, clinically in 1). Among these both FDG PET and single-voxel proton MRS showed false negative results (each method twice), whereas multi-voxel proton MRS always permitted us to establish the correct diagnosis. The present study demonstrates the higher diagnostic accuracy of multi-voxel proton MRS, in comparison with single-voxel proton MRS and FDG PET, for the differentiation of the radiation-induced necrosis and tumor recurrence. Its use is especially important in mixed lesions with co-existence of both post-irradiation changes and viable neoplasm. Monitoring of the treatment response by serial multi-voxel proton MRS seems to be reasonable during follow-up of patients with brain metastases after radiosurgery.     

Prognostic value of magnetic resonance imaging-guided stereotactic biopsy in the evaluation of recurrent malignant astrocytoma compared with a lesion due to radiation effect

OBJECT: The prognostic value of differentiating between recurrent malignant glioma and a lesion due to radiation effect by performing stereotactic biopsy has not been assessed. Thus, this study was undertaken to determine such value. METHODS: Between 1995 and 2001, 114 patients underwent magnetic resonance (MR) imaging-guided stereotactic biopsy to differentiate lesions caused by a recurrence of malignant astrocytoma and by radiation effect. All patients had previously undergone tumor resection (World Health Organization Grade III or IV) followed by radiotherapy. Disease diagnosis based on biopsy and patient characteristics were assessed as predictors of survival according to results of a multivariate Cox regression analysis. The diagnosis determined with the aid of biopsy was compared with that established during a subsequent resection in 26 patients. Survival following stereotactic biopsy was markedly increased in patients suffering from radiation effect compared with those harboring recurrent malignant glioma (p < 0.0001). In patients with radiation effect on biopsy, an increasing patient age (p < 0.05), having had two compared with one prior resection (p < 0.05), and a decreasing time from radiotherapy to biopsy (p < 0.001) were factors associated with decreased survival. Nevertheless, in patients with biopsy-defined radiation effect at second progression or with an age younger than 50 years the survival rate remained higher than that in patients with recurrent tumor on biopsy (p < 0.01). A biopsy-based diagnosis of radiation effect obtained less than 5 months after radiotherapy was not associated with an increased rate of patient survival compared with a diagnosis of recurrent malignant glioma on biopsy (p = 0.286). Eighty-six percent of lesions initially determined to be due to radiation effect on biopsy fewer than 5 months after radiotherapy were characterized as recurrent glioma by a mean of 11 months later. In contrast, only 25% of lesions initially diagnosed as attributable to radiation effect on biopsy more than 5 months after radiotherapy were classified as recurrent glioma a mean of 12 months later (p < 0.05). CONCLUSIONS: With the aid of stereotactic biopsy the authors demonstrated prognostic significance in differentiating recurrent malignant astrocytoma from a lesion due to radiation effect in patients presenting more than 5 months after having undergone radiotherapy. In patients who presented earlier than 5 months after radiotherapy, radiation effect on biopsy was not associated with an improved rate of survival compared with that in patients harboring recurrent malignant astrocytoma.     

脊髓血管母细胞瘤的MRI特点

【摘要】〓目的〓分析探讨脊髓血管母细胞瘤的MRI表现特征。方法〓回顾性分析经手术病理证实的7例脊髓血管母细胞瘤的临床及MRI表现。全部患者均行MRI平扫及增强扫描。结果〓单发6例,多发1例,共有脊髓血管母细胞瘤病灶8个,所有病灶均位于髓内。其中,延髓1个,颈段4个,胸段2个,腰段1个。肿瘤多呈点状、结节状、香肠状或不规则形状,肿瘤在MRI T1WI呈等或稍低信号,T2WI呈稍高信号,增强扫描上下径<20 mm的病灶呈明显、均匀强化,上下径>20 mm的病灶呈明显不均匀强化,其内可见多发流空的血管影;7例患者均伴有不同程度脊髓空洞或水肿。结论〓脊髓血管母细胞在MRI中具有特征性的影像表现,MRI对诊断脊髓血管母细胞瘤具有重要价值。     

Usefulness of FDG-PET in monitoring effects of the modality therapy for central nervous system malignant lymphoma: report of three cases

We have reported three cases of central nervous system malignant lymphoma in which FDG-PET was useful in monitoring therapeutic effects. Case 1: A 53-year-old man complained of gait and memory disturbance. An MRI of the patient's brain showed enhanced mass lesions in the bifrontal lobe. An FDG-PET showed markedly high uptake of the tracer, which means a higher metabolism of glucose. The tumor was biopsied and the histological diagnosis was diffuse B cell lymphoma. The patient received chemotherapy and external irradiation therapy. Case 2: A 64-year-old woman suffered memory disturbance and left hemiparesis. An MRI showed a right frontal mass lesion, and FDG-PET showed high uptake of glucose. After the histological diagnosis was determined as diffuse large B cell lymphoma, the patient received the same therapy as case 1. Case 3: A 55-year-old woman suffered right hemianopsia. An MRI showed an enhanced lesion in the right basal ganglia and an FDG-PET showed high uptake of glucose. After the histological diagnosis was determined as diffuse large B cell lymphoma, the patient received the same therapy as case 1 and 2. In all cases, high uptake of glucose disappeared on the PET after initial chemotherapy, although an enhanced lesion continued on MRI even after radiation. FDG-PET was useful in monitoring the therapeutic effects of malignant lymphoma. These results indicate that we were able to confirm the effectiveness of the therapy in the early stage.     

Diffuse low-density areas in white matter on CT scans after intracarotid ACNU infusion--report of three cases.

Since 1984, we have treated 11 malignant glioma patients with intracarotid infusion of ACNU [1-(4-amino-2-methyl-5-pyrimidinyl)-methyl-3-(2-chloroethyl)- 3-nitrosourea hydrochloride] in addition to surgical removal and irradiation. We experienced three patients, who showed clinical manifestation of leukoencephalopathy and computed tomographic (CT) findings of diffuse low-density areas in the white matter on the side of ACNU infusion. Two of the three patients showed an additional CT finding of ring enhancement in the temporo-occipital region. The histological diagnosis of the first case was radiation necrosis, while that of the others was recurrent tumor with coagulation necrosis in the surrounding brain. Our experience suggests that intracarotid ACNU infusion increases the hazard of radiation necrosis, and the optimum dose and effective mode of administration should be evaluated.     

脑内原发性淋巴瘤的MRI诊断

目的回顾性分析脑内原发性淋巴瘤MRI特点及病理改变,旨在提高对该病的MRI诊断水平。方法分析17例经手术病理证实的脑内原发性淋巴瘤的MRI表现,并与病理结果对照分析。结果(1)单发或多发病灶靠近中线区或脑表面,多发病灶占59%,易侵及额顶叶白质、胼胝体及基底节区;(2)T1WI呈低或稍低信号17例,T2WI呈等信号或稍高信号14例,占82%,坏死及出血少见;(3)灶周水肿及占位效应以轻度到中度为主;(4)强化方式以“握拳”样或团块状显著均匀强化为主,肿瘤可沿脑脊液播散。结论脑内原发性淋巴瘤的MRI表现具有一定的特异性,多数情况下综合分析可在术前作出正确诊断,但需与脑内多种疾病相鉴别。     

A clinical and magnetic resonance spectroscopy study of a brain tumor in a patient with segmental neurofibromatosis

Introduction

Segmental neurofibromatosis 1 (segmental NF-1) is a rare genodermatosis caused by somatic mutations in the NF-1 gene. It consists of localized characteristic skin lesions. A serial study using magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) of a brain tumor in a 16-year-old patient with segmental NF-1 is reported.

Case report

A 16-year-old boy with congenital dorsal scoliosis and segmental NF-1 was evaluated for bilateral optic atrophy. Neurological examination showed an isolated tetra pyramidal syndrome. The cerebral MRI showed a bilateral brain lesion involving the basal ganglia, optic pathways, temporal lobes, and the midbrain. Serial MRSs showed a decreased N-acetylaspartate (NAA)/creatine ratio and increased choline/creatine ratio. An increase in the myoinositol (MYO)/creatine ratio and the presence of a lipid/lactate peak were also recorded. A neuroimaging follow-up with MRI and MRS performed 2 years later showed similar findings.

Comments and conclusion

We describe an MRS study of a brain tumor in a patient with segmental NF-1 for the first time. The MRS study showed similar findings, described earlier in rare studies of patients with the classic form of NF-1. MRS is a noninvasive technique for detecting the presence of tumor tissue in the brain through its metabolic activity. MRS plays an important role in clinical studies and it can be used to differentiate malignant and nonmalignant brain lesions from normal brain tissue.     

Changes in 1H-MRS in glioma patients before and after irradiation: the significance of quantitative analysis of choline-containing compounds

The evaluation of the response to radiation therapy in brain tumor patients is a major and an important issue. Although CT and MRI can measure changes in tumor size, it is difficult to use these imaging methods to evaluate the viability or the proliferation activity of a tumor. In this study, we investigated the metabolite changes in glioma patients using 1H-MRS from before to after radiation therapy, to see whether or not early metabolic changes occur during therapy. Seven patients with histologically proven glioma (1 astrocytoma, 1 anaplastic astrocytoma, 2 oligoastrocytoma, 1 oligodendroglioma, 2 glioblastoma) were examined by means of 1H-MRS using a point-resolved spectroscopy (PRESS) sequence with a repetition time of 2,000 ms and echo times of 68 ms, 136 ms and 272 ms. The 1H-MRS was evaluated by both the spectrum pattern and the quantification of the metabolites. As to radiation therapy, each patient received a total dose of 64.8 Gy (1.8 Gy/fraction) with a 10-MeV linear accelerator. The results revealed that the concentration of choline-containing compounds (Cho) was 4.55 +/- 1.08 mmol/kg wet weight before radiation therapy and was reduced to 2.69 +/- 0.56 mmol/kg wet weight (p < 0.01) after radiation therapy. Moreover, both the N-acetylaspartate (NAA) peak and creatine/phosphocreatine (t-Cr) peak were lower after radiation therapy than before. The peaks of both the lipids (Lip) and lactate (Lac) were higher after radiation therapy than before. In conclusion, Cho concentration is thought to be a useful marker for the evaluation of early post-radiation response. The effect of radiation therapy can be evaluated according to the value of Cho. Further long-term MRS study is needed to prove whether or not the decrease of the Cho value in the present study will change before recurrence at later stages.     

Subependymoma of the lateral ventricles

Four subependymomas of the lateral ventricle were reviewed with regard to clinical presentation, neuroimaging features, treatment, histopathological features, and long-term follow-up. There were two male and two female patients ranging in age from 27 to 60 years (mean 48.3 years). While two patients presented with symptoms and signs of raised intracranial pressure, two others were found incidentally during neuroimaging investigations to have intraventricular tumors. Neuroimaging characteristics of these tumors included no paraventricular extension, iso- or hypodensity with minimal enhancement on computerized tomography (CT), or iso- or hypointensity on T1-weighted and hyperintensity on T2-weighted magnetic resonance images (MRI). The usual finding on MRI was of no or scarce contrast enhancement, but one case showed heterogeneous enhancement. Three patients underwent total resection of the tumor and one underwent partial resection. No patients received postoperative radiation therapy. All patients have been doing well 4.8 to 15.4 years (mean 8.8 years), after surgery. Although there are no absolutely specific features to distinguish these tumors from other intraventricular tumors preoperatively, subependymoma should be kept in mind for differential diagnosis, as this tumor may safely be removed without sacrificing contiguous normal tissue and with good long-term results.     

Primitive neuroectodermal tumor arising 8 years after chemotherapy and radiotherapy for acute lymphoblastic leukemia: case report

We report a case of primitive neuroectodermal tumor (PNET) arising 8 years after chemotherapy and radiotherapy for acute lymphoblastic leukemia. A 15-year-old boy with a history of acute lymphoblastic leukemia, at the age of 7, underwent chemotherapy and 14Gy of radiotherapy to the whole brain. He was admitted to our department due to the development of aphasia, right hemiparesis and generalized convulsive seizure. MRI showed an irregularly enhanced mass in the left frontal lobe. A gross total removal of the tumor was performed and histological examination showed it to be PNET. Postoperatively, the patient underwent 20Gy of radiotherapy to the whole brain and 42Gy of local radiotherapy. Follow-up MRI showed no evidence of recurrent tumor 4 months after the radiotherapy. This tumor was thought to be a secondary brain tumor arising in this survivor of childhood acute lymphoblastic leukemia and it is a rare complication of successful leukemia treatment.     

Case of unifocal orbital langerhans cell histiocytosis in an adult

A 34-year-old man had a 3-month history of left upper eyelid swelling and pain. Computed tomography showed osteolytic lesion of the left frontal bone. Magnetic resonance imaging (MRI) revealed a mass lesion with heterogeneously gadolinium enhancement and extension to both the lateral orbit and the frontal base. We performed mass resection via left frontotemporal craniotomy to diagnose the lesion. Pathological findings of the specimen were Langerhans cell histiocytosis (LCH). Systemic investigations revealed no sign of the disease elsewhere. The patient was diagnosed with unifocal orbital LCH and received neither chemotherapy nor radiotherapy. Follow-up MRI has shown no recurrences 2 years after surgery. Although orbital LCH rarely occurs in adults, it should be considered in differential diagnosis of orbital tumor. The patients with unifocal orbital LCH required no treatment in addition to mass resection.     

A case of subcutaneous malignant lymphoma with dura mater lesion

A 63-year-old male was admitted to our hospital, complaining of a scalp mass located at the frontoparietal area of his head. He noticed that it had been growing for 2 months. The mass was elastic hard and non-moving. Computed tomography demonstrated a subcutaneous mass with low density and which was enhanced homogeneously. The skull just below the mass was slightly destroyed, but the structure remained. Magnetic resonance imaging (MRI) demonstrated a mass with low signal intensity on both the T1 weighted image and the T2 weighted image. Gd-DTPA study showed homogeneous enhancement and showed also that the dura just below the mass was enhanced. At this point we couldn't diagnose it confidently, but suspected this lesion to be a malignant lymphoma. We made a general examination, but no other lesion was found. A biopsy of the subcutaneous mass was performed under local anesthesia. The histological diagnosis was large-cell type B-Cell lymphoma. The tumor was treated with chemotherapy, CHOP (cyclophosphamid, doxorubicin, vincristin predonisolone). It responded to this chemotherapy and disappeared. We treated this lesion without radiation therapy. We report a case of subcutaneous malignant lymphoma treated successfully with a minimum invasive method.     

Radiological features of primary central nervous system lymphoma

Radiological features of 12 cases of primary malignant lymphoma of the central nervous system with histological confirmation were reviewed. Ten patients had primary intracranial lymphoma, and two spinal. Angiography yielded no specific findings. CT appearances varied widely. Any positive relationships were not found between histologic types of tumors and patterns of contrast enhancement in the present cases as well as in those reported previously. Gd-DTPA was used in two patients. All lymphomas showed low to isointensity signals on T1-WI and high signal intensities on rho-WI and T2-WI. Although MRI gave no additional informations to those on CT with regard to the differential diagnosis, it proved to be a very accurate, non-invasive method of providing better delineation of tumor on multiplanar basis. Use of Gd-DTPA improved quality of T1-WI by markedly enhancing the tumor. It is generally difficult to distinguish primary from secondary spinal lymphoma, but two spinal epidural lymphomas in the present series were considered primary, as we could detect no other lesion elsewhere in the body. We expect that MR imaging would lead to an improvement in the detection of lesion in the paravertebral area.     

胰腺神经内分泌肿瘤的CT和MRI表现

目的探讨胰腺神经内分泌肿瘤的影像特征。方法分析43例经手术后病理证实的胰腺神经内分泌肿瘤的CT和MRI资料,并与手术病理结果对照。结果 43个病灶平均大小为(25.00±1.82)mm,23个病灶出现坏死囊变;CT平扫15个病灶呈等密度,28个病灶呈稍低密度;43个病灶T1WI均呈低/稍低信号,27个病灶T2WI呈高/稍高信号,16个病灶T2WI呈等信号;26个病灶见包膜;30个病灶显示清晰轮廓;24个病灶增强扫描动脉期病灶即明显强化,8个呈延迟强化,5个呈向心性强化,6个呈轻度强化。结论胰腺神经内分泌肿瘤形态及CT和MRI动态增强扫描具有特征性表现,影像学检查对诊断其具有重要价值。     

Unusual MR appearance of intracranial dissemination from cervical glioblastoma

We reported a rare case of cervical glioblastoma with intracranial dissemination at an early stage of clinical course and reviewed the literature. An 8-year-old girl presented with failure of vision 3 months prior to admission to our hospital. Neurological examination on admission disclosed no definitive abnormalities except for bilateral visual disturbance and optic atrophy. Cranial MR images revealed a homogeneously enhancing tumor in the left sylvian fissure. Multiple spotty T2-hyperintensity lesions without contrast enhancement were also disclosed in bilateral cerebellum. Spinal MR images showed an enhancing tumor at C7 and tiny enhancing lesions on the surface of T11. The patient underwent an uneventful excision of the exophytic tumor at C7. The histological diagnosis was glioblastoma. The enhancing tumor in the left sylvian fissure treated by Linac stereotactic radiotherapy with a marginal dose of 38.4Gy in 12 fractions has diminished, whereas the residual tumor at C7 remained unchanged after radiation of 44Gy. In contrast, the multiple spotty lesions without contrast enhancement dispersedly spread in the cerebellum and infiltrated into brain stem despite 4 courses of chemotherapy using ifosfamide, cisplatin, and etoposide. Stereotactic biopsy of the multiple spotty lesions in the cerebellum was performed. Histological examination revealed anaplastic astrocytoma. The patient died 2 weeks after the biopsy despite additional chemotherapy and focal irradiation to the cerebellum. Early detection and selection of optimal therapeutic strategies are important in management of spinal glioblastoma with subarachnoid dissemination, since neuroradiological findings and therapeutic sensitivity are varied according to differentiation of disseminated tumors.