Manjila Sunil, Miller Erin, Awadallah Amad, Murakami Shunichi, Cohen Mark L, Cohen Alan R
Division of Pediatric Neurosurgery, Rainbow Babies and Children's Hospital, Cleveland, Ohio, USA.
J Neurosurg Pediatr. 2013 Jul;12(1):13-20. doi: 10.3171/2013.3.PEDS12400. Epub 2013 May 3.
True ossification within benign brain tumors is rare, and the molecular mechanism for this process is poorly understood. The authors report a case of ossified choroid plexus papilloma (CPP) and analyze it to help elucidate the underlying molecular basis of osteogenesis in benign brain tumors. A 21-year-old man presented with headache and depression that progressed over years. Computed tomography, MRI, and angiography demonstrated a large heavily calcified fourth ventricular tumor with a vascular blush and no hydrocephalus. The tumor was resected and was found to be an ossified CPP. Immunohistochemical staining for VEGF, Sox2, BMP-2, osterix, osteopontin, and osteocalcin was performed in an attempt to elucidate the mechanism of bone formation. The tumor was extensively ossified with mature bone trabeculae. Immunostaining for VEGF was positive. Additional staining showed the presence of osteocalcin in this ossified tumor but not in samples of nonossified CPPs collected from other patients. Staining for osterix and osteopontin was equivocally positive in the ossified CPP but also in the nonossified CPPs examined. The presence of osteocalcin in the ossified CPP demonstrates that there is true bone formation rather than simple calcification. Its appearance within cells around the trabeculae suggests the presence of osteoblasts. The presence of osterix suggests that a pluripotent cell, or one that is already partially differentiated, may be differentiated into an osteoblast through this pathway. This represents the first systematic immunohistochemical analysis of osteogenesis within choroid plexus tumors.
良性脑肿瘤内真正的骨化很少见，对此过程的分子机制了解甚少。作者报告了一例骨化性脉络丛乳头状瘤（CPP）病例，并对其进行分析以帮助阐明良性脑肿瘤中骨生成的潜在分子基础。一名21岁男性出现头痛和抑郁症状，持续数年。计算机断层扫描、磁共振成像和血管造影显示一个巨大的重度钙化的第四脑室肿瘤，伴有血管充血，无脑积水。肿瘤被切除，发现是一个骨化性CPP。对血管内皮生长因子（VEGF）、Sox2、骨形态发生蛋白-2（BMP-2）、osterix、骨桥蛋白和骨钙素进行免疫组织化学染色，试图阐明骨形成机制。肿瘤广泛骨化，有成熟的骨小梁。VEGF免疫染色呈阳性。进一步染色显示该骨化肿瘤中有骨钙素存在，但从其他患者收集的非骨化性CPP样本中没有。骨化性CPP中osterix和骨桥蛋白染色呈弱阳性，在检查的非骨化性CPP中也呈弱阳性。骨化性CPP中骨钙素的存在表明存在真正的骨形成而非单纯钙化。其在小梁周围细胞内的出现提示有成骨细胞存在。osterix的存在表明一个多能细胞或一个已经部分分化的细胞可能通过这条途径分化为成骨细胞。这是脉络丛肿瘤内骨生成的首次系统性免疫组织化学分析。
