专家视角 颅内囊性病变总结(2):Rathke裂囊肿、松果体囊肿、胶样囊肿
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图片来源:Sharifi G, Amin Darozzarbi AA, Paraandavaji E, Lotfinia M, Kazemi MA, Hajikarimloo B, Jafari A, Mohammadi E, Davoudi Z, Akbari Dilmaghani N. Vertical triband flag sign for differential diagnosis of Rathke's cleft cyst. World Neurosurg X. 2023 Dec 12;21:100260.
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Axial and sagittal non-contrast CT (A-C), T1WI (D), T2WI (E) FLAIR (F), SWI (G), DWI (H) and gadolinium enhanced T1WI (I) showing an intrasphenoidal cystic lesion. Notice small T1-weighted hyperintense and T2-weighted hypointense nodule with blooming in SWI. Contrast enhanced T1WI shows rim enhancement with internal enhancing septa-like structure. Axial T2WI (J), sagittal T1WI (K) and contrast enhanced T1WI (L) showing recurred mass at 11-month follow-up. CT, computed tomography; T1WI, T1-weighted imaging; T2WI, T2-weighted imaging; FLAIR, fluid attenuated inversion recovery; SWI, susceptibility weighted imaging; DWI, diffusion weighted imaging.图片来源:Lee DI, Lee KM, Kim EJ. Huge intrasphenoidal Rathke's cleft cyst: a case description and analysis of the literature. Quant Imaging Med Surg. 2023 Dec 1;13(12):8864-8868.
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Brain MRI sagittal section images at the midline of Patients 1, 2, 5, and 9. The depth of the anterior pituitary gland (bracket) is marked on the images. A pituitary Rathke cleft cyst was found in Patient 9 (arrow) 图片来源:Hsu RH, Lee NC, Chen HA, Hwu WL, Chang TM, Chien YH. Late-onset symptomatic hyperprolactinemia in 6-pyruvoyl-tetrahydropterin synthase deficiency. Orphanet J Rare Dis. 2023 Nov 10;18(1):351.
2.松果体囊肿先天性松果体囊肿非常多见,大多无临床症状,部分患者可有头痛等表现。大体标本表现为光滑柔软的单房囊肿,囊壁为黄褐色或黄色,囊内容物为清亮的液体或呈黄色,囊内可含有出血成分。对于松果体囊肿和/或松果体囊性变的形成机制不明,有以下几种学说:①是一种正常变异;②由原来应分化为神经胶质的原始细胞残留演变为囊肿;③因第三脑室顶部闭合障碍残留形成囊肿;④松果体实质发生液化、囊变形成囊肿;⑤在胚胎发育中,内衬于原始脑室系统的神经上皮发生折叠、内卷或外翻,形成一袋状囊腔,凸向脑室内或伸出脑室外,袋颈离断,形成囊肿。松果体囊肿囊壁组织学上分为三层:最外层为纤维结缔组织层;中间层由松果体实质成分组成;内层为神经胶质细胞层,常伴有含铁血黄素的沉着。图片
Midsagittal MR CISS before (A) and after surgery (B) demonstrating a pineal cyst leading to a narrowed Sylvian aqueduct (arrow) without hydrocephalus.
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A Skin incision; greater occipital nerve (N). B Craniotomy exposing the transverse sinus. C Dural incision alongside the transverse sinus. D and E Dissection of bridging vein (V). F Pineal cyst (C) surrounded by thick arachnoid (A). G Bimanual dissection. H Resected pineal cyst (C). I + J Endoscopic view into the third ventricle showing massa intermedia (M) and posterior commissure (PC). K Endoscopic view to the roof of the third ventricle with a 45° endoscope shows the large internal cerebral veins (IV). L Microscopic view of the resection cavity showing gross total cyst resection. M Preservation of the bridging vein after cyst removal. N Dural closure. O Bone flap fixation with miniplates 图片来源:Fleck S, Damaty AE, Lange I, Matthes M, Rafaee EE, Marx S, Baldauf J, Schroeder HWS. Pineal cysts without hydrocephalus: microsurgical resection via an infratentorial-supracerebellar approach-surgical strategies, complications, and their avoidance. Neurosurg Rev. 2022 Oct; 45(5): 3327-3337.先天性松果体囊肿在CT、MRI上多表现为圆形或椭圆形囊性病变,80%的囊肿直径<1cm,囊壁薄而均匀,厚度一般≤2mm,光滑完整,与灰质呈等信号或等密度;囊内容物的CT值与脑脊液接近或稍高于脑脊液,信号强度呈类似于脑脊液的长T1长T2水样信号,在T1WI上55%~60%囊肿内容物信号强度稍高于脑脊液,在FLAIR像上囊液呈低信号,信号强度稍高于脑脊液,增强扫描60%囊肿出现囊壁轻中度强化。图片
(a) Midline sagittal FIESTA magnetic resonance imaging showing a large pineal cyst with an intracystic hemorrhage. (b) Midline sagittal FIESTA magnetic resonance imaging showing an average sized pineal cyst. (c) T1-weighted image with contrast-enhancement showing a small sized pineal cyst.图片

REF.邱立军,原小军,乔宏伟.先天性松果体囊肿CT及MRI诊断分析[J].中国煤炭工业医学杂志,2012,15(02):186-188.
3.胶样囊肿该病最早是由Wallmann于1858年描述,于1922年由William Dandy实行了第一例第三脑室胶样囊肿切除术。该病发病率极低,国外报道大致发病率在所有颅内肿瘤中的比例约为0.2%~2%,可发生于任何年龄,但症状多数出现于20~50岁之间。胶样囊肿起源于神经上皮组织,属于先天性神经上皮性囊肿,为脑室室管膜、脉络膜丛在形成过程中变异而成。该类肿瘤多数起源于脑室系统,其中99%起源于第三脑室孟氏孔周围,多表现为第三脑室胶样囊肿。第三脑室胶样囊肿CT表现通常为高密度,少数也可以表现为等密度或低密度。最常见的表现是T1WI高信号,T2WI高信号,胶样囊肿实质无强化,边缘可有或无强化,强化原因与囊壁含血管有关。Khoury等认为囊肿的MRI信号及CT密度反应了囊肿内容物的粘稠度,T2WI低信号及CT高密度的囊肿内容物更为粘稠,这为术前治疗方案的评估提供了一定的参考。
患者可能长期没有症状,而一旦第三脑室胶样囊肿生长到一定大小,可在第三脑室产生活瓣作用甚至堵塞第三脑室,导致急性梗阻性脑积水症状,常有剧烈头痛伴恶心呕吐,视力下降,癫痫发作甚至导致患者猝死。还有部分患者尽管没有脑积水症状,但表现为顺行性遗忘、幻嗅等精神症状,原因考虑为肿瘤直接压迫第三脑室周围结构产生的以精神症状为主的表现。部分急性脑积水患者改变头位症状可有缓解,考虑为第三脑室再通脑脊液循环稍通畅所致。猝死原因考虑为急性脑积水导致脑疝或肿瘤直接刺激下丘脑致功能紊乱致心跳骤停。还有学者报道极少数胶样囊肿有合并出血现象,而一但发生,易出现急性梗阻性脑积水症状,这也是导致患者猝死的原因。由于胶样囊肿的瘤壁极为菲薄,有学者报道曾有一例患者胶样囊肿自发破裂,致严重无菌性脑炎而需紧急处理。鉴于此,多数学者主张脑室胶样囊肿一但发现应尽快手术治疗,以防远期并发症。脑室胶样囊肿的大小一般为5~25mm。小的脑室胶样囊肿可能长期没有症状,而一但大于10mm,可能出现严重症状。Turel等学者认为若第三脑室胶样囊肿较小,小于10mm,且无任何症状,脑室系统无扩大的患者可以密切观察保守治疗,建议每年复查头颅核磁观察病变情况。凡是有临床症状的胶样囊肿或者最大径大于10mm的脑室胶样囊肿一但发现应尽快手术治疗,以防远期严重并发症。而直径小于10mm且无任何临床症状,脑室系统无扩大的,需向患者及家属讲明病情,结合患者家属意愿,决定行手术治疗或密切观察随访。该病治疗的目的主要是全切胶样囊肿,解除邻近压迫,疏通脑脊液循环通路。主要有立体定向胶样囊肿穿刺、开颅囊肿切除术和内镜下囊肿切除术。由于立体定向胶样囊肿穿刺很难剥净囊壁,易复发,当前国内外主要采取后两种手术方案。
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REF.周加华,冯达云,杨迪等.脑室胶样囊肿的临床特点及诊断治疗[J].中华神经外科疾病研究杂志,2018,17(03):245-248.图片
Localization of the cyst in the third ventricle (A). The cyst was wedged between the splayed columns of the fornix, not obstructing the left foramen of Monro (B). A viscous substance hardened after formalin fixation with a thin fibrous capsule was observed when the cyst was sectioned (C,D).图片
365建站Combined double mechanisms underlying the sudden death due to a colloid cyst of the third ventricle. 图片来源:Montana A, Busardò FP, Tossetta G, Goteri G, Castaldo P, Basile G, Bambagiotti G. Diagnostic Methods in Forensic Pathology: Autoptic Findings and Immunohistochemical Study in Cases of Sudden Death Due to a Colloid Cyst of the Third Ventricle. Diagnostics (Basel). 2024 Jan 1;14(1):100.图片
MRI showing an obstructive hydrocephalus measuring 21.8 mm (labelled). A colloid cyst measuring 9 mm is present (arrow). 图片来源:Nadeem A, Espinosa J, Lucerna A. Colloid Cyst Presenting With Severe Headache and Bilateral Leg Weakness: Case Report and Review. Cureus. 2023 Nov 24;15(11):e49347.图片
Axial CT images without contrast demonstrate a well-defined homogeneous hypodense nodular lesion (blue arrows) located between the foramina of Monro and the anterior portion of the third ventricle, causing symmetrical expansion of the lateral ventricles (red arrows).
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365建站客服QQ:800083652(A) Coronal T2-weighted MR images at different levels better characterize the described lesion as a well-defined fluid-filled cystic mass (blue arrows) located in the midline, in the topography of the anterior portion of the third ventricle, obstructing the foramina of Monro with resultant marked hydrocephalus (white arrows). (B) Axial FLAIR image demonstrates a still hyperintense signal exhibited by the described lesion (blue arrows), even with CSF signal suppression, postulating a higher protein content within the lesion compared to CSF. Some periventricular areas also exhibit hyperintense signals (red arrows), consistent with the transependymal flow caused by the existing obstructive hydrocephalus. (C) Axial T1-weighted MR image demonstrates an isointense signal exhibited by the lesion with no signs of enhancement postcontrast administration (blue arrows) (D).图片
Macroscopic picture of the contents of the lesion approached by endoscopy, after being exposed to controlled freezing and peeling off the covering capsule, revealing mucoid material of different textures and colors. 图片来源:Mansour MA, Khalil DF, Hamdi A, Bayoumi M, El-Salamoni MA, Elsoulia A, Lasheen AA, Kamel AE, Nawara M, Ayad AA. Intraventricular sizeable colloid cyst with atypical radiological features: A case report and evidence-based review. Radiol Case Rep. 2023 Aug 15;18(10):3753-3758.
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CT 示室间孔旁圆形高密度结节1.0×1.0 第3
CT 示室间孔旁圆形高密度结节1.0×1.0 第3脑室以上略扩大,无强化。来源:刘红权,王志杰.胶样囊肿的CT与MR影像诊断5例[J].中国现代医生,2010,48(27):94-95.
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