Furuno Yuichi, Nishimura Shinjitsu, Kamiyama Hironaga, Numagami Yoshihiro, Saito Atsushi, Kaimori Mitsuomi, Nishijima Michiharu
Department of Neurosurgery, Aomori Prefectural Central Hospital, Aomori, Japan.
Neurol Med Chir (Tokyo). 2008 Feb;48(2):72-6. doi: 10.2176/nmc.48.72.
A 15-year-old man presented with headache. Magnetic resonance (MR) imaging revealed a large extraaxial tumor with cyst at the right frontotemporal region. The solid part of the tumor was homogeneously enhanced on T(1)-weighted MR imaging after injection of gadolinium. Digital subtraction angiography of the external carotid artery revealed sunburst appearance corresponding to the tumor, which was fed by the right middle meningeal artery. His headache worsened and computed tomography revealed enlargement of the tumor and intracystic hemorrhage, so emergent operation was performed. At surgery, the tumor strongly adhered to the dural membrane, and was obviously extraaxial. The tumor and cyst were gross totally removed. The attachment site at the dura mater was resected. Histological examination showed solid growth of small round cells with uniform round nuclei and minimal cytoplasm. Immunohistochemical staining showed the cells were positive for MIC-2 (CD99). The MIB-1 labeling index was 53%. The histological diagnosis was peripheral-type primitive neuroectodermal tumor (pPNET). Following surgery, radiation therapy and chemotherapy were given. Ewing's sarcoma and pPNET form a family of small round cell tumors arising in the bone or soft tissue. MIC-2 is a useful marker in the differential diagnosis. Good prognosis may be attained if complete surgical excision of intracranial pPNET is achieved.
一名15岁男性因头痛就诊。磁共振成像显示右侧额颞区有一个带囊肿的巨大轴外肿瘤。注射钆后，肿瘤的实性部分在T1加权磁共振成像上呈均匀强化。颈外动脉数字减影血管造影显示肿瘤呈“旭日”状外观，由右侧脑膜中动脉供血。他的头痛加重，计算机断层扫描显示肿瘤增大并伴有囊内出血，遂紧急进行手术。手术中，肿瘤与硬脑膜紧密粘连，明显位于轴外。肿瘤和囊肿被大体完全切除。切除了硬脑膜上的附着部位。组织学检查显示小圆形细胞呈实性生长，细胞核均匀圆形，细胞质极少。免疫组织化学染色显示细胞对MIC-2（CD99）呈阳性。MIB-1标记指数为53%。组织学诊断为外周型原始神经外胚层肿瘤（pPNET）。手术后给予放疗和化疗。尤因肉瘤和pPNET属于起源于骨或软组织的小圆形细胞肿瘤家族。MIC-2是鉴别诊断中的一个有用标志物。如果能完全手术切除颅内pPNET，可能会获得良好的预后。
