小脑蚓部表皮样囊肿附1例报告及文献复习

Epidermoid Cyst of the Cerebella Vermis: A Case Re-port and Literature Review

表皮样囊肿(EC)是起源于异位的胚胎上皮细胞,约占颅内肿瘤的0.2%～1.8%,发生在小脑蚓部的极为少见。本文通过对1例罕见的发生在小脑蚓部的表皮样囊肿手术所见及其术后病理特征分析,进一步探讨颅内表皮样囊肿的临床表现、影像学特点及治疗方式。方法与结果:术前常规行头颅CT及核磁共振检查,T_1加权像显示小脑蚓部球状异常高信号影,T_2加权像异常高信号影,大小约4.8cm×4.6cm×4cm,信号不均,其内可见点状、线状及环状长T_1异常信号(类似血管流空影)无明显增强。不同于典型的表皮样囊肿在T_1加权像为异常低信号影,T_2加权像异常高信号影的特征性表现。于全麻下行后正中枕下人路占位显微切除术,术中发现小脑蚓部皮质下4mm深处有明显的囊性占位,囊壁透明,囊内见粪汁样黄色液体及白色线形体似蠕虫样物2条,1条长约3cm,直径约1.0mm,一端成结,另1条长2.0cm,另取出毛发3根,0.5cm～1.5cm长。大结节者位于右侧小脑半球囊壁处,与周围脑组织粘连紧密,显微分离,完整切除囊壁。术后核磁共振检查示肿瘤全切除,病理检查结果示表皮样囊肿。结论:颅内表皮样囊肿表现多样,影象学特征复杂,有时术前诊断困难。手术应强调全切除囊壁及内容物,预后良好。

BACKGROUND & OBJECTIVES: Intracranial epidermoid cysts(EC) are uncommon benign congenital tumors and rarely occur in the cerebellar vermis. In the present article, we illustrated a rare case of the cerebellar vermis EC and the atypical MRI and surgical findings. The clinical symptomatology, neuro-images,and surgical management of intracranial EC were also discussed. METHOD & RESULTS: A 19 year-old female patient with MRI appearance of a cystic lesion in cerebellar vermis was reported. The lesion was inhomogeneous and hyperintensive on both T_1 and T_2 weighted image (T_1WI & T_2WI). There was no enhancement after contrast injection. It is different from the usual characteris-tics of most EC, which is heterogenous and hy-pointensive on T_1WI. The cyst contents dis-played linear and circular patterns, and were simi-lar to the flow void pattern of veins on MRI.A sub-occipital craniotomy was performed, and a pearly globe cyst of about 4.8×4.6×4cm in size was found. The cyst was well encapsulated, mul-ti-lobulated, and included 2 worm-like structures. The cyst was total removed. The histopathological diagnosis was an epidermoid cyst. CONCLUSION: Intracranial epidermoid cysts can present in many different appearances on MRI. The appearance depends on the cyst contents. Total resection is the only curative treatment for EC.However, complete resection should not be attempted at the risk of injuring the vital neurovascular structures. Postoper-ative follow-up with CT or MRI should be performed.