颅内非颅神经主干的神经鞘瘤的影像学表现

目的 报告4例经手术病理证实的颅内非颅神经主干的神经鞘瘤，并结合文献讨论其组织发生及CT、MRI表现。方法 回顾性分析4例颅内非颅神经的神经鞘瘤，复习其病理特点，分析其起源与CT、MRI表现。结果 CT平扫肿瘤多为低等混杂密度，瘤内多有坏死、囊变区，甚至以大的囊性变为主要特征；MR平扫肿瘤T1WI以低和稍低信号，T2WI为不均匀高信号；CT及MR增强扫描实质部分及囊壁呈中等程度强化。病理的苏木精和伊红染色有2种组织学形态，即Antoni A型和Antoni B型，免疫组织化学染色S—100蛋白强阳性。结论 颅内非颅神经主干的神经鞘瘤影像学表现与颅神经鞘瘤相似，但有更高的囊变率，若在非颅神经位置出现类似颅神经鞘瘤的影像学征象时，应想到此瘤的可能。

The imaging manifestation of intracranial schwannomas not arising from cranial nerves

Objective To report 4 cases of operation-confirmed intracranial schwannomas not arising from cranial nerves, and to discuss the histogenesis and CT and MRI manifestation combining with the literature. Methods CT and MRI findings of these 4 intracranial schwannomas were analyzed retrospectively and their pathologic characteristics were reviewed. Results The tumors demonstrated low-iso mixed density with necrotic and cystic areas. Large degeneration even became the prominent characteristics on CT scan. Low-signal to iso-signal intensity on T 1-weighted images and heterogeneous high-signal intensity on T 2-weighted images were revealed. The solid portion and the wall of the tumors were moderately enhanced on enhanced CT and MRI scans. Hematoxylin and eosin-stained sections showed two corresponding histological patterns: Antoni Type A and Antoni Type B pattern. The tumor cells exhibited a strong positive staining pattern for s-100 protein. Conclusion The imaging manifestations of these tumors were similar to that of cranial nerve schwannomas except that the former had higher cystic degeneration rate. We should take that diagnosis into consideration when the mass is not located on cranial nerve but its image feature resembles schwannomas.