6例胚胎发育不良性神经上皮肿瘤患者的临床病理学分析

背景与目的:胚胎发育不良性神经上皮肿瘤(dysembryoplastic neuroepithelial tumor,DNT)是一种少见的良性混合性神经元-胶质肿瘤,探讨其临床病理学特征及鉴别要点.方法:回顾性分析苏州大学附属第一医院和苏州市立医院2009年3月—2021年1月经病理学检查确诊的6例DNT患者的资料,归...     

Mixed germ cell tumors with abundant sarcomatous component in the temporal lobe after radiochemotherapy of neurohypophyseal germinoma: a case report

We report a case of intracranial germ cell tumor that showed pathological changes from neurohypophyseal germinoma to mixed germ cell tumors consisting exclusively of undifferentiated sarcomatous component after radiochemotherapy. Three surgical specimens and autopsied brain from the patient were histologically examined. An initial specimen from the neurohypophyseal tumor was diagnosed as germinoma with a two-cell pattern. Five years later, after repeated radiochemotherapy, the second specimen resected from the right temporal lobe showed mixed germ cell tumors consisting of the three components of germinoma, choriocarcinoma, and immature teratoma. Six months later after intensive radiotherapy, the right temporal tumor recurred and was surgically removed. The histological diagnosis was mixed germ cell tumors with abundant immature teratoma component. The patient died of uncontrollable tumor growth with repeated intratumoral hemorrhages. The autopsied brain showed sarcoma with angionecrosis. This pathological alteration indicated an increase in the sarcomatous component after undergoing various treatments. We discuss the histological changes of intracranial germ cell tumor modified by treatment.     

A case of ductal carcinoma with squamous differentiation in malignant phyllodes tumor

Carcinoma derived from the lining epithelial cells in malignant phyllodes tumor is a rare neoplasm of the breast and belongs to the category of carcinosarcoma. We report a case of ductal carcinoma with squamous differentiation arising in malignant phyllodes tumor. A 54-year-old woman was admitted with a rapidly enlarging left breast mass. A breast tumor with a diameter of 6 cm was located mainly in the left outer area of the breast. Mammography revealed a high-density mass with an irregular margin and ultrasound showed a cystic tumor. A pathological diagnosis of ductal carcinoma with squamous differentiation was made by fine needle aspiration and a core needle biopsy. She underwent neoadjuvant chemotherapy followed by a modified radical mastectomy with a skin flap. Histopathological examination revealed that the invasive ductal carcinoma with squamous differentiation originated from the lining epithelial cells in malignant phyllodes tumor and that there was no transition area between the carcinomatous and the sarcomatous component. She experienced lung and facial bone metastases, microscopic features of which were consistent with the sarcomatous component of the original breast carcinosarcoma. This is an extremely rare case of carcinosarcoma and the histopathological findings and review of the literature are discussed.     

Brain tumors in surgical neuropathology of intractable epilepsies, with special reference to cerebral dysplasias

Surgical specimens from 30 patients (13 males and 17 females) with intractable epilepsy with brain tumors and allied lesions were histopathologically examined: 4 of nonneurogenic origin (1 angiolipoma with cortical dysplasia and 3 cavernous hemangiomas), 2 low-grade fibrillary astrocytomas, 1 pleomorphic xanthoastrocytoma, 3 pilocytic astrocytomas with nuclear polymorphism, 1 oligoastrocytoma, 9 gangliogliomas, 3 gangliogliomatous lesions combined with tuberous sclerosis-like dysplastic changes, and 7 undetermined lesions suspected of being mixed glioma, dysembryoplastic neuroectodermal tumor (DNT), or dysplasia. They were all located supratentorially: in the temporal lobe in 21, frontal lobe in 6, and parietooccipital lobe in 3. The age of onset was under 20 years in most patients. Some kinds of dysplasias, such as focal cortical dysplasia, glioneuronal heterotopia, and clustered neurons in the hippocampus and amygdaloid nucleus, were combined in 11 cases, especially those with age of onset under 10 years. Pilocytic astrocytoma-like features were seen in 5 of the gangliogliomas and 3 of the undetermined lesions, and DNT-like features in 2 of the former and 3 of the latter. Gangliogliomas, pilocytic astrocytomas, mixed gliomas, DNTs, and dysplasias may be closely interrelated in the development of intractable epilepsies of young patients.     

间变性节细胞胶质瘤复发为幕上原始神经外胚层肿瘤一例报告并文献复习

背景与目的：间变型节细胞胶质瘤非常少见,恶变总是发生在胶质成分。目前已有少量病例显示神经元成分的恶性转化。本文报道一例原发瘤为间变性节细胞胶质瘤,术后8个月复发为幕上原始神经外胚层肿瘤的病例。方法：观察并分析原发瘤和复发瘤的病理形态特征和免疫组化标记。结合文献讨论间变性节细胞胶质瘤转变为幕上原始神经外胚层肿瘤的可能机制。结果：患儿8岁。镜下见第一次切除的左颞叶肿瘤：部分区域肿瘤细胞密集分布。细胞较小,核染色较深,部分瘤细胞呈小片状,细胞稍大,核圆形或多角形,染色质淡。肿瘤组织中另可见散在或聚集向神经元分化的不同阶段的肿瘤细胞。细胞较大,有明显淡红染的胞浆,胞核空泡状,有核仁。有的似分化较成熟的节细胞。网状染色见瘤组织中纤维组织明显增生。免疫组化结果显示：GFAP灶性（＋）、NSE（＋）、S100（＋）、Nestin（＋）、VIM（＋）、Des（＋）。似神经元分化的大细胞则有NSE和S-100的阳性表达。病理诊断：伴有纤维增生的间变性节细胞胶质瘤。术后8个月左颞部复发肿瘤中除了仍见明显的纤维组织增生外,另见小或中等大小的肿瘤细胞密集排列,瘤细胞更异型,核分裂多见。未见较成熟分化的细胞。免疫组化显示：GFAP灶性（＋）、S100（＋）、NFP（＋）、Neuronal class III beta-tubulin（＋）。提示肿瘤细胞向神经元和胶质成分双向分化。病理诊断幕上原始神经外胚层肿瘤。结论：节细胞胶质瘤可以出现胶质和神经成分的恶性转化。     

Papillary Glioneuronal Tumor

Objective and importance Papillary glioneuronal tumor is a recently described neoplasm composed of gliovascular pseudopapillae associated with intervening neuronal cells ranging from neurocytes to ganglion cells. This tumor is not currently included in the WHO classification of tumors of the central nervous system. We describe a new case of papillary glioneuronal tumor and analyze the data for a series of further 15 patients from international literature.Clinical presentation A 27-year-old man presented to us for generalized seizure. CT and MRI showed a cystic tumor with mural nodule in the left frontal lobe.Intervention Frontal craniotomy with gross total removal of the tumor was performed. Histopathological examination was positive for papillary glioneuronal tumor.Conclusion The clinical, radiologic, and pathological features of our case are strikingly similar to those of the previous reported cases. A review of the literature disclosed only 15 other cases of these tumors.It is important that every new case of PGNT is reported to allow its recognition and classification.     

Radiation-induced osteosarcomas after treatment for frontal gliomas: a report of two cases

Most radiation-induced osteosarcomas of the skull are reported to arise in the facial bone or paranasal sinus after radiotherapy for retinoblastoma and/or pituitary adenoma. Here we report two cases of radiation-induced osteosarcoma in the paranasal sinus after treatment for frontal glioma. Case 1 was a 56-year-old woman who underwent surgical resection of a left frontal tumor in October 1990. The histological diagnosis was a low-grade glioma, and radiotherapy of 54 Gy was administered. Sixteen years later, in September 2006, the patient noted an enlarging subcutaneous mass in the right frontal region. CT showed an osteolytic mass in the right frontal sinus. An open biopsy established the histopathological diagnosis of osteosarcoma, and the patient subsequently died of rapid tumor regrowth. Case 2 was a 58-year-old man who underwent partial removal of a bifrontal tumor in May 1996. The histological diagnosis was anaplastic oligoastrocytoma, and radiotherapy of 56 Gy was administered. Twelve years later, in March 2008, the patient was readmitted to our hospital for reasons of marked deterioration in general physical condition. Tumor recurrence was suspected in the left frontal lobe, and CT demonstrated an osteolytic mass in the left frontal and ethmoid sinus. A secondary operation was performed, and the pathological specimens were diagnosed as osteosarcoma. Radiotherapy was readministered, but the subject died of rapid tumor regrowth. From these clinicopathological findings, both cases were diagnosed as radiation-induced osteosarcoma. Radiation-induced osteosarcomas appeared 16 and 12 years after radiotherapy in cases 1 and 2, respectively. As the prognosis of radiationinduced osteosarcoma is poorer than that of primary osteo-sarcoma, careful attention is required for consideration of the long-term survival of patients with glioma.     

Malignant transformation eight years after removal of a benign epidermoid cyst: a case␣report

Summary Malignant transformation of benign epidermoid cysts is rare and their prognosis remains poor. A 56-year-old woman presented with left facial hypoesthesia and photophobia in the left eye. She had undergone removal of a benign epidermoid cyst in the cerebellopontine angle 8 years previously. Magnetic resonance imaging of the brain revealed a cystic lesion in the left cerebellopontine angle. The cyst wall was enhanced by gadolinium-DTPA. She underwent removal again and the histopathologic diagnosis was squamous cell carcinoma. Gamma knife radiosurgery was performed on the remnant lesion with a marginal dose of 15 Gy. The tumor shrank rapidly for 2 months after radiosurgery, but recurred 9 months later. She underwent radiosurgery again with a marginal dose of 12 Gy. A gradual increase in the size of the enhanced lesion was seen during the 4-month follow-up period subsequent to the second radiosurgery. Careful observation, employing serial magnetic resonance images, is necessary for incompletely resected epidermoid cysts because intervals before malignant transformation reportedly range from 3 months to 33 years. Newly identified contrast enhancement strongly indicates malignant change in epidermoid cysts. Gamma knife radiosurgery may be useful for short-term control of intracranial squamous cell carcinomas, but long-term effects are presently unknown.     

Unclassified glioneuronal tumor with advanced lipidization

Lipidization is observed only occasionally in primary neuroectodermal tumors of the central nervous system. It may reflect lipomatous transformation of tumor cells into xanthomatous and/or adipocyte-like cells. We report a unique case of mixed glioneuronal tumor with marked lipomatous changes in a young patient with intractable epilepsy. MRI revealed a well-circumscribed lesion in the right temporal lobe. Histopathological findings showed the pleomorphic tumor with numerous cells containing large lipid droplets, resembling mature adipocytes, that were arranged in clusters or scattered within the neoplastic tissue. The tumor was composed of both glial and neuronal elements. Some tumor cells displayed features intermediate between glial and neuronal cells. The reticulin fibers were limited to blood vessels. Mitotic figures, vascular proliferation, and necrosis were absent, and MIB-1 labeling index was less than 1%. Diffuse immunoreactivity for GFAP and S100-protein was observed. In some heavily lipidized cells, the lipid droplets were surrounded by a cytoplasmic rim of GFAP immunoreactivity. Numerous cells exhibited immunostaining for NSE and synaptophysin. This is the first documented case of glioneuronal tumor with extensive lipomatous transformation, which might be considered as a heavily lipidized unclassified pleomorphic glioneuronal tumor or a variant of lipoganglioglioma with marked pleomorphism and severe lipidization.     

A malignant solitary fibrous tumor in the retroperitoneum

Solitary fibrous tumor in the retroperitoneum is rare. We report a case of a malignant solitary fibrous tumor in the retroperitoneum, with a lymph node metastasis, in a 48-year-old-woman. Computed tomography and magnetic resonance imaging indicated a mass in the retroperitoneal space beside the left kidney, with a swollen paraaortic lymph node. Surgical findings revealed a circumscribed tumor in the retroperitoneum. A pathohistological examination revealed two separate components: a benign hypocellular area rich in collagen fibers and a malignant hypercellular area with nuclear atypia. The histological finding for the lymph node was the same as that in the hypercellular area. Because of these findings, the mass was diagnosed as malignant solitary fibrous tumor. Only surgical treatment was performed, and the patient is alive without recurrence 2.5 years after the surgery. Immunohistochemical staining for p53 was positive in the malignant component but negative in the benign area, indicating that the expression of p53 may play a critical role in the malignant transformation of solitary fibrous tumor.     

脑膜恶性孤立性纤维性肿瘤临床病理学观察

目的：探讨脑膜恶性孤立性纤维性肿瘤的临床病理特征、核磁共振特点、鉴别诊断及治疗和预后。方法：报道一例脑膜恶性孤立性纤维性肿瘤临床病理、影像学资料并复习文献。结果：患者,男性,65岁,临床主要表现为四肢乏困,无力,记忆力差,MRI示左颞枕叶可见约8.5cm×6.5cm×6cm的囊实性病灶,术中发现肿瘤累及脑膜,与周围脑组织界限清楚,送检肿瘤组织灰白色均质状,有囊性变。镜检：肿瘤由交替性分布的细胞丰富区和细胞稀疏区组成,细胞排列呈条束状、席纹状或无结构样,部分区域呈血管外皮瘤样结构,部分区域细胞丰富密集,有异型性,核分裂象多见（〉4个/10HPF）,未见明显坏死。免疫表型：肿瘤细胞Vimentin、CD99、bcl-2、CD34弥漫阳性,p53弱阳性,Ki-67〉10%。病理诊断：左颞枕叶脑膜恶性孤立性纤维性肿瘤。结论：脑膜恶性孤立性纤维性肿瘤非常罕见,确诊主要依靠病理形态学及免疫组织化学标记,并与脑的其它梭形细胞肿瘤鉴别。治疗以手术完整切除为主,可预防性放疗并密切随访。     

Use of fractional anisotropy value by diffusion tensor MRI for preoperative diagnosis of astrocytic tumors: case report

The fractional anisotropy (FA) value calculated by diffusion tensor MRI can indicate the degree of directionality of water diffusion in astrocytic tumors. Here, we report a case of anaplastic astrocytoma in which FA proved invaluable for the preoperative differential diagnosis. A 60-year-old man complained of headache, and underwent routine neuroimaging and DTI. The routine images suggested a low-grade glioma in the left temporal lobe, based on lack of enhancement on MRI with contrast medium and lack of tumor staining on angiograms, whereas FA value was very high. Based on these findings, a preoperative diagnosis of high-grade glioma was suspected. The surgical specimen exhibited the histological features of anaplastic astrocytoma with a high density of spindle shaped cells and low vascularity. In this report, we discuss the relationship between FA and other characteristics of the present tumor, and discuss the utility of FA measurement in astrocytic tumors.     

Pleomorphic xanthoastrocytoma as a component of a temporal lobe cystic ganglioglioma: a case report

We report a case of pleomorphic xanthoastrocytoma (PXA) as a component of a ganglioglioma in a 13-year-old Japanese boy. Magnetic resonance imaging showed a large cystic lesion with an enhanced mural nodule of the left temporal lobe. Microscopic examination of the tumor showed that it was composed of two distinct neoplastic components: dysplastic ganglion cells and a PXA. There were gradual transitions between the two neoplastic components, and the PXA constituted the gliomatous component of the ganglioglioma. The PXA component showed spindle-shaped and pleomorphic large cells with lipidized cytoplasm. The tumor cells were surrounded by numerous reticulin fibers. Immunohistochemically, the ganglion cells were negative for glial fibrillary acidic protein (GFAP), but showed positive staining for a 70-kDa neurofilament protein, synaptophysin, and NeuN. In contrast, PXA cells were positive for GFAP but negative for neuronal markers. Our case is therefore histologically classified as ganglioglioma with PXA as the glial component. These results suggested that PXA and ganglioglioma share a common origin and that the combination of PXA-ganglioglioma would be positioned along the spectrum between PXA and ganglioglioma. Alternatively, these results may support the hypothesis that PXA originates from glioneuronal progenitor cells capable of generating astrocytic and neuronal cell types.     

A case of anaplastic pleomorphic xanthoastrocytoma presenting with tumor bleeding and cerebrospinal fluid dissemination

Pleomorphic xanthoastrocytoma (PXA) has been considered an astrocytic tumor with a relatively favorable prognosis. However, PXA cases having several recurrent patterns with poor prognosis have been reported in recent years, and a new concept of anaplastic PXA has been proposed. The present case was a 59-year-old woman who presented with tumor bleeding onset and cerebrospinal fluid dissemination. The patient had sudden-onset right hemiparesis, aphasia, and consciousness disturbance and was admitted to a local area hospital. After emergency surgery had removed the hematoma, postoperative contrast-enhanced CT scan revealed a left temporal tumor. A second surgery was therefore performed for initial tumor removal 2 months later. Histopathological findings showed that the tumor was typical PXA with strong pleomorphism and xanthomatous changes and contained an ependymoma-like component in the center area. However, endothelial proliferation and mitosis were more remarkable compared to ordinary PXA. The MIB-1 labeling index was 9.8% high. From these findings, the histopathological diagnosis was anaplastic PXA. The patient underwent surgery to remove recurrent tumors 5 and 16 months later. The patient died 36 months after the first onset, and CT revealed glioblastoma-like findings and cerebrospinal fluid dissemination. This case report is the first case in which PXA presented with tumor bleeding onset. Histopathological findings suggested anaplastic PXA from the first surgical specimens, and PXA recurred many times. We thus believe that the patient displayed primary anaplastic PXA rather than secondary anaplastic PXA that results in malignant transformation. The present case was reported at the 23rd annual meeting of the Japan Society of Brain Tumor Pathology (April 21–22, 2005, Tokyo, Japan).     

脑膜恶性孤立性纤维性肿瘤临床病理学观察

目的:探讨脑膜恶性孤立性纤维性肿瘤的临床病理特征、核磁共振特点、鉴别诊断及治疗和预后。方法:报道一例脑膜恶性孤立性纤维性肿瘤临床病理、影像学资料并复习文献。结果:患者,男性,65岁,临床主要表现为四肢乏困,无力,记忆力差,MRI示左颞枕叶可见约8.5cm×6.5cm×6cm的囊实性病灶,术中发现肿瘤累及脑膜,与周围脑组织界限清楚,送检肿瘤组织灰白色均质状,有囊性变。镜检:肿瘤由交替性分布的细胞丰富区和细胞稀疏区组成,细胞排列呈条束状、席纹状或无结构样,部分区域呈血管外皮瘤样结构,部分区域细胞丰富密集,有异型性,核分裂象多见(>4个/10HPF),未见明显坏死。免疫表型:肿瘤细胞Vimentin、CD99、bcl-2、CD34弥漫阳性,p53弱阳性,Ki-67>10%。病理诊断:左颞枕叶脑膜恶性孤立性纤维性肿瘤。结论:脑膜恶性孤立性纤维性肿瘤非常罕见,确诊主要依靠病理形态学及免疫组织化学标记,并与脑的其它梭形细胞肿瘤鉴别。治疗以手术完整切除为主,可预防性放疗并密切随访。     

A case of an unclassified tumor closely resembling dysembryoplastic neuroepithelial tumor with rapid growth

We describe a rare case of a tumor resembling dysembryoplastic neuroepithelial tumor. A 3-year-old girl had a generalized convulsion as the initial symptom, without other neurological deficits. Computed tomography showed a hypodense lesion with calcific hyperdensity in the left frontal lobe associated with deformity of the overlying calvarium. Four months later, she had a second seizure, and computed tomographic scan showed that the lesion had increased in size. Subtotal removal of the tumor was performed, and the postoperative course was uneventful without radiation therapy. Histological examination revealed a cortical lesion in which an oligodendrocyte-like area and an astrocyte-like area with cytological atypia were observed. Although the clinical course and the radiological findings closely resembled those of dysembryoplastic neuroepithelial tumor, specific glioneuronal elements were not found histologically. Daumas-Duport reported a complex form of dysembryoplastic neuroepithelial tumor that contained glial nodules in addition to a specific glioneuronal element. The histological findings of the glial nodules in this case were quite similar to those she described. We conclude that this could be an unclassified tumor closely resembling dysembryoplastic neuroepithelial tumor without a specific glioneuronal element. This case was registered at the Japan Brain Tumor Reference Center (No. 98-012)     

Dysembryoplastic neuroepithelial tumor of the midbrain tectum: a case report

Dysembryoplastic neuroepithelial tumor (DNT) is a relatively new nosologic entity. First described in 1988, it is now included in the “neuronal and mixed neuronal-glial tumours” category in the revised 2000 World Health Organization (WHO) Classification of Tumours of the Nervous System. The collective experience of more than 3000 reported cases indicates that, with only rare exceptions, DNTs are cerebral cortical lesions. At present, the actual incidence of extracortical DNT is unknown. We describe, the clinicopathologic features of the first tectal DNT. The patient was a 51-year-old man with a 2-month history of pulsatile headaches. On neurologic examination, the only abnormality was gait ataxia. Magnetic resonance imaging (MRI) demonstrated a midbrain tumor involving the tectum. It was hypointense on T1-weighted images and featured an iso-to hyperintense nodule at its center. The nodule showed enhancement upon contrast administration. No aqueductal obstruction or intraventricular extension of tumor was detected. The tumor was approached supratentorially and removed completely. The mucoid tumor was well demarcated from neural tissue. Histopathologically, it was a typical DNT, exhibiting a nodular pattern of growth with a “specific glioneuronal component”. This case report documents the first DNT to arise in the midbrain tectum and focuses on the problem of diagnosing this uncommon tumor at extracortical sites.     

Clinical Characteristics and Surgical Management of Patients with Temporal Lobe Gangliogliomas

OBJECTIVE To review the clinical features and surgical treatment for patients with temporal lobe gangliogliomas. METHODS Patients with temporal lobe gangliogliomas who underwent resection of temporal lobe tumors, confirmed by surgical pathology, seen between September 1998 and November 2004 at the West China hospital, were selected. Medical records were reviewed for age at diagnosis, age at onset of seizures, delay between seizure onset and tumor diagnosis, types and frequencies of seizures, EEG results, extent of surgery, and pathologic diagnosis. The follow-up periods varied from 12 to 60 months (mean 30 months). RESULTS Eighteen patients were identified, including 14 males and 4 females. Age at operation ranged from 4 years to 34 years (mean 17.6 years). All patients underwent at least one surgical procedure. Fifteen tumors were classified as WHO Grade I lesions, and 3 as WHO Grade II lesions. None of patients experienced a tumor recurrence. Among the patients, 85% had complete and sustained seizure relief. CONCLUSION Complex partial seizures and auras were the common presenting symptom of these patients. The follow-up suggested good relief from the seizures after surgery and a low risk for tumor recurrence and malignant progression.     

Glioneuronal tumors of the central nervous system

Advances in the immunohistochemical detection of neuron-specific and neuronal-associated antigens have resulted in the discovery of neuronal elements in certain primary human brain tumors. The results have been not only to expand what neuropathologists commonly recognize as gangliogliomas, including the tumors now known as glioneurocytic tumor with neuropil rosettes and papillary ganglioneuroma, but also to expand the spectrum of tumor types to now include tumors such as central neurocytoma, dysembryoplastic neuroepithelial tumor, and desmoplastic infantile ganglioglioma. These discoveries have helped us to better understand the biology of these tumors and to refine our classification of them. Distinctions among these tumors include sites of predilection, such as the temporal lobe with the dysembryoplastic neuroepithelial tumors, and a spectrum of clinical aggressiveness that spans indolent “quasihamartomatous” lesions, such as the dysembryoplastic neuroepithelial tumor, to high-grade, highly aggressive tumors, such as the supratentorial primitive neuroectodermal tumor (World Health Organization Grade IV). Many of these tumors also commonly exhibit a glial component, as determined by both their histologic appearance and their immunoreactivity for glial fibrillary acidic protein. This review covers these recently described lesions, including the desmoplastic infantile ganglioglioma, the dysembryoplastic neuroepithelial tumor, the papillary glioneuronal tumor, the glioneuronal tumor with neuropil rosettes, and the mixed glioblastoma-cerebral neuroblastoma (supratentorial primitive neuroectodermal tumor), as well as the known tumors, ganglioglioma, medulloepithelioma, and medulloblastoma. For pathologists confronted by this growing array of tumors and subtypes, it is appropriate to focus on them and understand the differential diagnosis to be considered when confronted by them.     

Rapid progression of rhabdoid components of a composite high-grade glioma and rhabdoid tumor in the occipital lobe of an adult

We report a very unusual case of a composite high-grade glioma and rhabdoid tumor in an adult. A 22-year-old woman presented with scintillating scotoma due to a solid tumor with surrounding brain edema in the right occipital lobe. The tumor was grossly resected. Histological examinations showed that the tumor was mainly composed of INI1-positive high-grade glioma tissue containing an INI1-negative rhabdoid component. She received radiation therapy and chemotherapy. Three months after the surgery, she again complained of visual disturbances, and tumor recurrence within the resection cavity was noted. A second operation was performed. The findings of histological examinations of the surgical specimen obtained during the second surgery were completely different from those of the specimen obtained during the initial surgery. Only the rhabdoid component showed remarkable proliferation and did not express INI1. Diffuse dissemination along the craniospinal axis eventually progressed, and she died 5 months after the initial diagnosis. We suggest that the inactivation of the INI1 gene affects potent proliferation activity and resistance to both chemotherapy and radiation therapy.