Gan Yee Chiung, Connolly Mary B C, Steinbok Paul
Division of Paediatric Neurosurgery, Department of Paediatric Surgery, University of British Columbia, 4480 Oak Street, #K3-159, Vancouver, BC, V6H 3V4, Canada.
Childs Nerv Syst. 2008 Jan;24(1):125-34. doi: 10.1007/s00381-007-0439-x. Epub 2007 Aug 7.
The role of the cerebellum in the pathogenesis of seizures remains controversial. Cerebellar origin of seizures, albeit rare, has been described in the literature in association with intrinsic lesions of the cerebellum. We present a unique case of a patient with medically intractable, secondary generalized epilepsy, associated with a superior cerebellar quadrigeminal arachnoid cyst.
A 9-year-old child presented with medically refractory secondary generalized epilepsy associated with recurrent headaches since 6 months of age. The child also had moderate intellectual impairment and autism. On the magnetic resonance imaging (MRI) of the head, he was noticed to have a small superior cerebellar arachnoid cyst in the quadrigeminal area that had increased in size slightly. Interictal electroencephalograph (EEG) was unable to localize the site of the epilepsy. Neurological examination was unremarkable.
A suboccipital craniotomy and supracerebellar infratentorial approach to the cyst was performed at 9 years of age. Intraoperative electrocorticography (ECOG) demonstrated epileptic activity from the cerebellar tissue adjacent to the cyst. The cyst was fenestrated, and the cyst wall was sent for histology. Seizure control improved dramatically after fenestration of the cyst.
This case provides strong evidence that, albeit rare, the cerebellum may be a source of epileptic activity due to compression by a lesion in the posterior fossa. Hence, in cases with intractable epilepsy of unknown supratentorial source, the differential diagnosis should include a posterior fossa lesion. The finding of a posterior fossa lesion in such cases, even if it is small and appears benign, should precipitate a discussion about the possible relationship between the posterior fossa lesion and the epilepsy.
小脑在癫痫发病机制中的作用仍存在争议。癫痫源自小脑的情况虽罕见，但文献中已有与小脑内在病变相关的描述。我们报告一例独特病例，患者患有药物难治性继发性全身性癫痫，与小脑上蚓部蛛网膜囊肿有关。
一名9岁儿童自6个月大起出现药物难治性继发性全身性癫痫，并伴有反复头痛。该儿童还存在中度智力障碍和自闭症。头颅磁共振成像（MRI）显示，其在四叠体区域有一个小的小脑上蚓部蛛网膜囊肿，囊肿大小略有增加。发作间期脑电图（EEG）无法确定癫痫发作部位。神经系统检查无异常。
患儿9岁时接受了枕下开颅手术及经小脑上幕下入路处理囊肿。术中皮层脑电图（ECOG）显示囊肿附近小脑组织有癫痫活动。囊肿被开窗，囊肿壁送去做组织学检查。囊肿开窗后癫痫控制情况显著改善。
该病例提供了有力证据，表明尽管罕见，但小脑可能因后颅窝病变的压迫而成为癫痫活动的来源。因此，对于幕上来源不明的难治性癫痫病例，鉴别诊断应包括后颅窝病变。在此类病例中发现后颅窝病变，即使病变较小且看似良性，也应引发关于后颅窝病变与癫痫之间可能关系的讨论。
