髓母细胞瘤的CT诊断(附50例分析)

 目前CT在诊断髓母细胞瘤方面虽有经验，但也经常遇到一些非典型CT表现的特殊病例误诊为其他颅内肿瘤。为进一步提高髓母细胞瘤的CT诊断水平，对经CT检查，并经手术病理证实的50例髓母细胞瘤总结如下。     

髓母细胞瘤的CT诊断(附50例分析)

目前ＣＴ在诊断髓母细胞瘤方面虽有经验 ,但也经常遇到一些非典型ＣＴ表现的特殊病例误诊为其他颅内肿瘤。为进一步提高髓母细胞瘤的ＣＴ诊断水平 ,对经ＣＴ检查 ,并经手术病理证实的 50例髓母细胞瘤总结如下。1　材料与方法　　 50例中 ,男 2 6例 ,女 2 4例。年龄2岁～ 37岁。主要临床表现 :头痛、呕吐、视力减退、走路不稳。全部病例经ＣＴ检查 ,并经手术病理证实。2　结果　　ＣＴ表现 :肿瘤位于小脑蚓部 38例 ,小脑半球 8例 ,第四脑室 4例。ＣＴ平扫均匀稍高密度区 2 3例 ,见图 1。混合密度区 1 2例 ,等密度区 9例 ,略均匀低密度区 4例…     

颅后窝髓母细胞瘤的治疗(附89例临床分析)

目的　对近几年收治的儿童髓母细胞瘤患者的临床资料进行回顾性分析 ,旨在提高对该疾病的认识和治疗效果。方法　 89例全部采用手术切除加术后放疗。结果　手术全切除 72例、次全切除 17例 ;术后 2例死于脑干功能衰竭 ,2例术后 2月出现脑积水 ,3例出现缄默症 ,2例上消化道出血 ,所有患者均有不同程度的发热 ;随访 5 2例 ,术后 3年无瘤生存 49例 ,桥小脑角 1例术后 7年原部位复发。结论　手术应尽量全切并注意保护脑干及蛛网膜下腔 ,若肿瘤较大者应首先分块切除中心部位 ,减少体积后再沿边界切除 ,以减少术后并发症 ;术后放疗应作为常规治疗手段 ,放疗范围及剂量应视患者年龄而定。     

髓母细胞瘤的放疗：附17例分析

髓母细胞瘤恶性程度高,术后极易复发,但对射线敏感,我科1962～1984年收治17例髓母细胞瘤术后病例,经全中枢神经系统照射,即:全脑照射DT25～30Gy,后颅凹40～50Gy。全脊髓预防DT30Gy,结果6/17存活5年以上。本瘤常发于小脑蚓部侵犯第四脑室而引起脑脊液循环障碍。为避免在放疗中发生颅压增高,放疗前应先行手术,尽量切除肿瘤。由于瘤细胞易随脑脊液播散,因此应行全中枢神经系统照射。     

儿童髓母细胞瘤的显微手术治疗——附24例报告

背景与目的：髓母细胞瘤是儿童常见的中枢神经系统恶性肿瘤，手术是其治疗的主要手段。本文通过对24例儿童髓母细胞瘤显微外科治疗分析，总结儿童髓母细胞瘤的显微手术经验。方法：收集1999-2007年我院经手术证实的儿童髓母细胞瘤24例，对其临床资料进行回顾性分析。其中男16例，女8例，平均年龄7．5岁，常见症状和体征为高颅压征和共济失调，全部患者均行显微手术治疗，术后辅助放射治疗。19例随访6个月至6年。结果：全组病例中，肿瘤全切21例，大部分切除2例，部分切除1例，手术死亡率4．2％（1／24），未出现严重并发症．患儿生存质量得到提高。结论：掌握显微手术方法和手术中注意事项，有利于提高肿瘤切除程度及减少手术并发症．手术后辅助放疗有利于改善预后。     

髓母细胞瘤的CT和MRI影像学分析及临床意义

目的:通过对髓母细胞瘤的CT 及MRI表现分析,加强对本病的认识,提高术前诊断的准确性并合理选择治疗方案.方法:对31例经手术、病理证实的髓母细胞瘤进行回顾性分析,所有病例均行 CT 和/或 MRI检查.结果:髓母细胞瘤好发于儿童,常见于小脑蚓部;成人髓母细胞瘤少见,多见于小脑半球.CT 平扫呈等或稍高密度影,增强扫描多强化明显.MRI扫描 T1 加权像呈低或等信号,T2 加权像呈略高或混杂信号,增强扫描强化明显.结论:髓母细胞瘤有特定的发生部位、年龄及影像学特征性;仔细分析CT和 MRI表现,可做出准确的术前诊断并指导制定治疗方案,改善预后.     

髓母细胞瘤干细胞

髓母细胞瘤和其他胚胎性脑肿瘤在形态和分化上同神经干细胞和祖细胞相似。通过人类肿瘤标本的基因表达研究和转基因鼠模型分析．提示多能外胚层小脑干细胞和谱系限制性的祖细胞可以通过基因的改变转化为髓母细胞瘤。这些分子的改变常常涉及到Wnt、Hedgehog和Notch等信号通路的组成性激活．这些信号通路在非肿瘤性神经干细胞中发挥重要作用。通过药物阻断Hedgehog和Notch信号通路在体外培养和体内均可抑制髓母细胞瘤的生长．这个可以证明对于肿瘤的发生和长期增殖所必须的小肿瘤干细胞亚群以上述信号通路为靶点阻滞是有效的。     

髓母细胞瘤的放射治疗：附34例疗效分析

背景与目的：髓母细胞瘤是儿童后颅窝常见的恶性肿瘤，手术联合术后放疗是公认的治疗方法，化疗的作用尚不肯定。本文回顾性分析34例髓母细胞瘤术后放疗和化疗的疗效。方法：1992年1月至2002年12月，34例经术后病理证实的小脑髓母细胞瘤患者在我院接受了术后放疗，全脑照射剂量为2850～3500cGy，后颅窝瘤床缩野加量照射2000-2500cGy，全脊髓照射剂量2960—3210cGy。14例接受了术后全身化疗。采用Kaplan—Meier法计算生存率，生存率之间的差异采用log—rank法检验。结果：全组5年总生存率58．8％，无瘤生存率53．2％；其中术后化疗组和未化疗组的5年总生存率分别是71．4％和50．1％(x^2=1．24，p=0．2662)，无瘤生存率分别是57．1％和50．2％(x^2=0．32，P=0．5714)。结论：髓母细胞瘤手术联合术后全脑全脊髓放疗的疗效确定，术后全身化疗未显著提高总生存率和无瘤生存率。     

颅后窝髓母细胞瘤的治疗（附89例临床分析）

目的对近几年收治的儿童髓母细胞瘤患者的临床资料进行回顾性分析，旨在提高对该疾病的认识和治疗效果。方法89例全部采用手术切除加术后放疗。结果手术全切除72例、次全切除17例；术后2例死于脑干功能衰竭，2例术后2月出现脑积水，3例出现缄默症，2例上消化道出血，所有患者均有不同程度的发热；随访52例，术后3年无瘤生存49例，桥小脑角1例术后7年原部位复发。结论手术应尽量全切并注意保护脑干及蛛网膜下腔，若肿瘤较大者应首先分块切除中心部位，减少体积后再沿边界切除，以减少术后并发症；术后放疗应作为常规治疗手段，放疗范围及剂量应视患者年龄而定。     

The prognostic significance of postoperative residual contrast enhancement on CT scan in pediatric patients with medulloblastoma

The clinical and therapeutic features of 20 patients with medulloblastoma treated at Childrens' Hospital and Medical Center, Seattle, from 1980 to 1987, were retrospectively analyzed with regard to prognosis. The overall actuarial 5-year survival rate was 63%, with 57% of patients free from recurrence at 5 years. Residual contrast enhancement on CT scans taken immediately postoperatively was associated with a significantly decreased 5-year recurrence-free survival rate; the 5-year recurrence-free survival rate was 100% for those patients without post-operative residual enhancement compared to 41% for those patients with residual enhancement. A high risk group of patients with residual contrast enhancement persisting one year following diagnosis was identified. No patient in this group survived without disease progression. Other factors, including sex, age at diagnosis, evidence of tumor dissemination, or extent of surgical resection as reported by the neurosurgeon, did not significantly influence prognosis.     

髓母细胞瘤的CT和MRI影像学分析及临床意义

目的：通过对髓母细胞瘤的CT及MRI表现分析,加强对本病的认识,提高术前诊断的准确性并合理选择治疗方案。方法：对31例经手术、病理证实的髓母细胞瘤进行回顾性分析,所有病例均行CT和／或MRI检查。结果：髓母细胞瘤好发于儿童,常见于小脑蚓部;成人髓母细胞瘤少见,多见于小脑半球。CT平扫呈等或稍高密度影,增强扫描多强化明显。MRI扫描T1加权像呈低或等信号,T2加权像呈略高或混杂信号,增强扫描强化明显。结论：髓母细胞瘤有特定的发生部位、年龄及影像学特征性;仔细分析CT和MRI表现,可做出准确的术前诊断并指导制定治疗方案,改善预后。     

Neuroradiology of pediatric posterior fossa medulloblastoma

Summary Medulloblastoma of the cerebellum is a common intracranial neoplasm in children and presents many faces in medical imaging. Characteristic or classic features, such as increased attenuation on unenhanced CT, midline location and well defined margins, are commonly present in childhood cases of posterior foassa medulloblastoma, although atypical imaging features are being noted more frequently with the increased dependence on MR as the diagnostic modality of choice. Carefully performed CT and MR both initially provide suitable geography and characteristics, but MR is superior in the detection of pre- or post-operative neoplastic spread elsewhere in the subarachnoid space. Accurate establishment of disease extent is essential in planning both surgical resection and adjuvant therapy.     

High dose chemotherapy with stem-cell transplantation in a metastatic medulloblastoma in an adult: a case report and review of the literature

Medulloblastoma is a rare tumor in adult. High doses of megavoltage irradiation of the posterior fossa have been resulted in a better survival (48 to 78% at 5 years) of the patient. It is sensitive to a wide variety of chemotherapy drugs, but adjuvant chemotherapy has not been proved effective in adults although data are limited. We report the case of a cerebellar medulloblastoma with bony and medullar metastases. High-dose chemotherapy with peripheral stem-cell transplantation was performed while the patient was in remission following conventional chemotherapy. Complete remission lasted for 8 months. This therapeutic approach of metastatic medulloblastoma might be of value as this tumor is chemosensitive and not cured by conventional treatment. Internal radiotherapy by Samarium-153 was also carried out and proved to be an effective palliative treatment of pain.     

Intra-arterial BCNU in the treatment of recurrent medulloblastoma

Two patients with recurrent medulloblastomas were treated with combined oral and intra-venous chemotherapy followed by intra-arterial BCNU. The 7 days course of oral and intra-venous chemotherapy consisted of CCNU and Procarbazin orally and Vincristine intra-venously (PCV), repeated after 6 weeks. Intra-arterial chemotherapy consisted of 4 cycles of BCNU. Both patients responded well to treatment, evaluated by CT scans. One of the patients died of a new local recurrence 6 months after initiation of chemotherapy, whereas the other patient remains well, without CT evidence of tumour 36 months after the start of the treatment. No serious adverse side-effects related to the treatment were seen.     

The microtubule stabilizer patupilone (epothilone B) is a potent radiosensitizer in medulloblastoma cells

Concurrent radiochemotherapy for medulloblastoma includes the microtubule disrupting agent vincristine; however, vincristine alone or as part of a combined treatment regimen is highly toxic. A major goal is therefore to replace vincristine with novel potent chemotherapeutic agents-in particular, with microtubule stabilizing and destabilizing compounds-with a larger therapeutic window. Here, we investigated the antiproliferative, cytotoxic and radiosensitizing effect of patupilone (epothilone B [EPO906]), a novel, non-taxane-related and nonneurotoxic microtubule-stabilizing agent in human medulloblastoma cell lines. The antiproliferative and cytotoxic effects of patupilone alone and in combination with ionizing radiation was determined in the 3 representative human medulloblastoma cell lines D341Med, D425Med, and DAOY. Patupilone alone effectively reduced the proliferative activity and clonogenicity of all medulloblastoma cell lines tested at picomolar concentrations (50-200 pM) and resulted in an at least additive anticlonogenic effect in combination with clinically relevant doses of ionizing radiation (2 or 5 Gy). Cell-cycle analysis revealed a sequential G2-M arrest and sub-G1 accumulation in a dose- and treatment-dependent manner after exposure to patupilone. In tumor xenografts derived from D425Med cells, a minimal treatment regimen with patupilone and fractionated irradiation (1 × 2 mg/kg plus 3 × 3 Gy) resulted in an extended tumor growth delay for the 2 single treatment modalities alone and a supra-additive treatment response for the combined treatment modality, with complete tumor regressions. These results demonstrate the potent efficacy of patupilone against medulloblastoma cell lines and indicate that patupilone represents a promising candidate to replace vincristine as part of a combined treatment strategy with ionizing radiation.     

A possible role for somatostatin receptor scintigraphy in the diagnosis and follow-up of children with medulloblastoma

The surgical resection of medulloblastoma (MB), the most frequent malignant brain tumor in children, often remains subtotal. To estimate the response to further treatment the residual tumor is monitored by CT or MRI. The interpretation of both imaging techniques is complicated by disturbances resulting from surgery and radiation. Our study searched for alternative imaging techniques and asked the following questions. 1) Do MB express somatostatin receptors (SSTR), 2) is SSTR scintigraphy a sensitive imaging technique for the follow-up and the detection of vital tumor tissue in children with MB, and 3) do the results of SSTR scintigraphy correlate with the in vitro analysis of MB tissue by SSTR autoradiography. We analyzed the SSTR status in 20 children with MB, aged 1 to 15 years. Sixteen SSTR scintigraphies using Indium-111-DTPA-D-Phel-pentetreotide were performed in 14 children. MB tissue of 14 children was analyzed by SSTR autoradiography using Iodine-125-Tyr3-octreotide. In 8 cases SSTR were measured by both methods in vivo and in vitro. In comparison with conventional imaging, results of SSTR scintigraphy were true positive in 7 of 7 patients, true negative in 9 of 9 patients, including one patient with false positive findings in MRI, false negative in only one patient with small spinal metastases (diameter < 3 mm) and false positive in none of the analyzed patients. In all cases with residual tumor (n = 3) and suspected relapse (n = 4) the diagnosis could be confirmed (n = 4) or excluded (n = 3), consistent with the results of MRI and tumor histology. All MB tissues analyzed by SSTR autoradiography (n = 14) showed an extremely high density of SSTR ranging from 4047 to 15526 dpm/mg MB tissue. MB (n = 8) which were analyzed by SSTR scintigraphy and autoradiography demonstrated consistent results in evaluation by both methods. In cases where the integrity of the blood-brain barrier was tested by Tc-99m-DTPA scintigraphy (n = 10), the SSTR-to-brain scintigraphy index confirmed the tumor specificity of radionuclide uptake. We conclude that 1) MB tissue expresses a particularly high density of SSTR, 2) the high density of SSTR in autoradiography correlates with a sensitive imaging of these tumors by SSTR scintigraphy, 3) SSTR scintigraphy might be a valuable imaging method for detection of vital MB tissue in patients with residual tumor or relapse.     

Etoposide-carboplatin association as ‘emergency’ up-front chemotherapy in a case of life-threatening adult medulloblastoma

Medulloblastoma is a rare tumor in the adult population. Current therapies include surgery and irradiation. Unlike in children, chemotherapy is not commonly used, and its potential has poorly been investigated to date. We report the case of an adult patient with disseminated medulloblastoma and fulminant neurological deterioration, precluding craniospinal irradiation. Emergency chemotherapy consisting of carboplatin (400 mg/m²) and etoposide (500 mg/m²) with intrathecal (i.t.) administration of cytosar and hydrocortisone was initiated. Impressive clinical response was achieved after the first cycle of chemotherapy, with the complete disappearance of the lesions detected by MRI. After 3 courses of chemotherapy, the patient underwent craniospinal irradiation (36 Gy to the entire neuraxis and 54 Gy to the posterior fossa). Two months after surgery, the patient was well, with complete clinical recovery, and a new MRI confirmed the disappearance of the lesions. Given the dramatic efficacy of the etoposide-carboplatin association (combined with i.t. cytosar), this regimen has to be considered in an emergency setting and seems to be a very attractive candidate to be investigated as first line therapy for poor risk medulloblastoma in adults.     

Cyclosphosphamide therapy of medulloblastoma: From the laboratory to the clinic and back again (and again and again)

Summary Medulloblastoma, the most common malignancy of childhood, was originally shown to be sensitive to cyclophosphamide in 1981. We have used combined laboratory and clinical investigations to demonstrate the synergy of cyclophosphamide and vincristine in the treatment of this tumor, the therapeutic gain associated with escalation of the dosage of cyclophosphamide, the consequence of and mechanisms underlying resistance of medulloblastoma to cyclophosphamide, the emerging importance of the neuroaxis as a site of relapse of medulloblastoma, and newer approaches, including intrathecal 4-hydroperoxycyclophosphamide and busulfan, to treat neuraxis disease. These studies serve as a paradigm for laboratory-clinical translational research.     

Histology predicts a favorable outcome in young children with desmoplastic medulloblastoma: a report from the children's oncology group

BACKGROUND:

Contemporary therapy for medulloblastoma results in adverse neurocognitive effects on young children, particularly those under the age of 3. Stratification of patients by risk group may allow toxic treatment to be avoided.

METHODS:

Seventy‐six patients diagnosed with medulloblastoma and enrolled on CCG‐9921 underwent central review of pathology, and histologic subtype was designated as desmoplastic or nondesmoplastic. Nonparametric event‐free survival (EFS) and survival (OS) curves were computed using the product limit (Kaplan‐Meier) estimates, and the log‐rank test was used to compare survival according to histologic subtype.

RESULTS:

Patients with desmoplastic medulloblastoma experienced a favorable EFS of 77% ± 9% and OS of 85% ± 8% compared with EFS of 17% ± 5% and OS of 29% ± 6% for patients with tumors in the nondesmoplastic group (P < .0001 for both EFS and OS comparisons). Patients without disease progression did not receive radiation therapy.

CONCLUSIONS:

Children less than 3 with desmoplastic histology of medulloblastoma represent a lower‐risk group for whom reduction of therapy, including elimination of radiation therapy, is an appropriate strategy. Cancer 2011. © 2011 American Cancer Society.