Gabel Brandon C, Levy Michael L, Crawford John R
Division of Neurosurgery, University of California, San Diego, California, USA.
Department of Neurosurgery, Rady Children's Hospital, San Diego, California, USA.
World Neurosurg. 2015 Sep;84(3):865.e1-5. doi: 10.1016/j.wneu.2015.03.054. Epub 2015 Apr 1.
Posterior fossa brain tumors are common in children. Symptoms typically develop when the tumors have reached sufficient size to cause compression of adjacent neural structures or cause obstructive hydrocephalus. Many tumors in this region originate from the tela choroidea and choroid plexus of the fourth ventricle. Enhancement of the fourth ventricular tela choroidea and choroid plexus is uncommon in children, and when such enhancement is present, it may represent early tumor growth.
A 5-year-old girl with a history of congenital nystagmus, for whom initial work-up was reported as negative, presented again several years later with headache, nausea, and vomiting. She was found to have a large posterior fossa lesion on repeat neuroimaging that was retrospectively seen on the first neuroimaging scan as prominent enhancement in the region of the fourth ventricular choroid plexus. The second patient presented with congenital nystagmus and a lingual tremor and was found to have a slowly growing lesion situated in the fourth ventricle. Initial imaging was read as nodularly enhancing tela choroidea, but subsequent scans revealed enlargement of the lesion.
The first patient underwent gross total resection, and neuropathology was consistent with an atypical teratoid rhabdoid tumor. The patient has done well with postoperative adjuvant therapies. In the second patient, resection of the lesion revealed ependymoma; the patient has done well after adjuvant radiation therapy.
Pediatric patients who have enhancing tela choroidea or choroid plexus without an obvious mass lesion of the fourth ventricle may harbor early tumors. Surveillance imaging in these patients may be warranted given the aggressive nature of certain posterior fossa tumors in children. Failure to recognize abnormal enhancement patterns in this region may lead to delayed diagnosis.
后颅窝脑肿瘤在儿童中很常见。当肿瘤长到足够大，足以压迫相邻神经结构或导致梗阻性脑积水时，症状通常才会出现。该区域的许多肿瘤起源于第四脑室的脉络膜组织和脉络丛。儿童第四脑室脉络膜组织和脉络丛强化并不常见，当出现这种强化时，可能代表肿瘤早期生长。
一名有先天性眼球震颤病史的5岁女孩，最初的检查报告为阴性，几年后再次出现头痛、恶心和呕吐症状。复查神经影像学检查发现她有一个大的后颅窝病变，回顾首次神经影像学扫描时发现第四脑室脉络丛区域有明显强化。第二名患者有先天性眼球震颤和舌震颤，发现第四脑室内有一个缓慢生长的病变。最初的影像学检查结果为脉络膜组织结节状强化，但随后的扫描显示病变增大。
第一名患者接受了肿瘤全切术，神经病理学检查结果与非典型畸胎样横纹肌样瘤一致。患者术后辅助治疗效果良好。第二名患者病变切除后病理结果为室管膜瘤；辅助放疗后患者恢复良好。
第四脑室脉络膜组织或脉络丛强化但无明显占位性病变的儿科患者可能患有早期肿瘤。鉴于儿童某些后颅窝肿瘤的侵袭性，对这些患者进行监测成像可能是必要的。未能识别该区域异常强化模式可能导致诊断延迟。
