松果体区肿瘤的影像学分析

Radiological analysis of pineal region tumors

目的探讨CT和MRI对松果体区肿瘤的诊断价值及在肿瘤治疗中的作用。方法对经开放手术病理诊断明确的72例松果体区肿瘤患者的CT和MRI资料进行回顾性分析。结果大部分松果体区肿瘤缺乏一致性较好的影像特征。总体上，混合性生殖细胞肿瘤、成熟畸胎瘤、非成熟畸胎瘤等含不同发生来源或多胚层组织的肿瘤形态欠规则，密度／信号混杂．囊实性混杂，强化不均匀。生殖细胞瘤、绒癌、松果体细胞瘤、松果体母细胞瘤等单一细胞肿瘤形态相对规则，密度／信号一致性较好，强化基本均匀。当混合性肿瘤或多胚层肿瘤以某一种组织成分为主时，影像学表现与单一细胞肿瘤相似。胶质瘤影像学表现差异较大，但多可依据与周围脑组织的关系，脑水肿部位，静脉移位方向做出诊断。脑膜瘤多较大，小脑幕／大脑镰强化“拖尾征”少见，其他征象典型，诊断不难。囊肿病理多样，表皮样囊肿破裂肉芽肿形成时影像表现与畸胎瘤类似。结论松果体区肿瘤中生殖细胞肿瘤、松果体实质细胞肿瘤影像学检查的局限性比较明显，难以进一步区分各种单一细胞肿瘤或多组织肿瘤，因此依据影像学表现做出治疗方案决定应慎重。

Objective To evaluate the diagnostic and therapeutic value of CT and MRI for pineal region tumors. Methods CT and MRI data of 72 cases definitely diagnosed as pineal region tumors pathologically by open surgery were retrospectively analyzed. Results Most pineal region tumors lacked imaging features with comparatively favorable regularity. In general, mixed germ cell tumors, mature teratomas and immature teratomas etc of multi-germinal layer origin showed irregular shapes, promiscuous CT density and MRI signals, mixed cystic-solid lesions and uneven enhancement. Germinomas, chorioepitheliomas,pinealocytomas and pinealoblastomas etc, which were all single-cell tumors, showed comparatively regular shapes, relatively consistent CT density and MRI signals and basically even enhancement. When mixed tumors or tumors of multi-germinal layer origin were dominated by some kind of ingredients, their imaging manifestations were similar to that of single-cell tumors. Though discrepancies existed between imaging manifestations of gliomas, diagnostic results could be made according to the relationship between tumors and their adjacent brain tissues, locus of brain edema and venous shift trend. Meningiomas were mostly large, strengthened ＂trailing sign＂ for tentorium of cerebellum/sickle of cerebrum was rare and other signs were typical, so there was no difficulty in their diagnoses. Cyst pathology diversified, but imaging presentations of granulomas resulted from epidermoid cyst rupture were similar to that of teratomas. Conclusion Due to evident limitations of imaging examinations of germ cell tumors and pineal parenchymal tumors among pineal region tumors, it is difficult to carry on further differentiation of any single-cell or multi-tissue tumors. Therefore, much attention should be paid to therapeutic plans made according to radiological manifestations.