Azab Waleed A, Salaheddin Waleed, Alsheikh Tarek M, Nasim Khurram, Nasr Mahmoud M
Department of Neurosurgery, Ibn Sina Hospital, Kuwait City, Kuwait.
Surg Neurol Int. 2014 Aug 7;5:124. doi: 10.4103/2152-7806.138364. eCollection 2014.
Colloid cysts are usually located at the rostral part of the third ventricle in proximity to the foramina of Monro. Some third ventricular colloid cysts, however, attain large sizes, reach a very high distance above the roof of the third ventricle, and pose some challenges during endoscopic excision. These features led to the speculation that for such a pattern of growth to take place, the points of origin of these cysts should be at areas away from the foramina of Monro at which some anatomical "windows" exist that are devoid of compact, closely apposed forniceal structures.
A review of the literature on anatomical variations of the structures in the vicinity of the roof of the third ventricle and on reported cases with similar features was conducted.
Colloid cysts may grow vertically up past the roof of the third ventricle through anatomical windows devoid of the mechanical restraint of the forniceal structures.
Some anatomical variations of the forniceal structures may allow unusually large sizes and superior vector of growth of a retro- or post-foraminal colloid cyst. Careful preoperative planning and knowledge of the pertinent pathoanatomy of these cysts before endoscopic excision is very important to avoid complications.
胶样囊肿通常位于第三脑室前部，靠近孟氏孔。然而，一些第三脑室胶样囊肿体积较大，在第三脑室顶部上方延伸至很高的位置，在内镜切除过程中带来一些挑战。这些特征引发了一种推测，即对于这种生长模式的发生，这些囊肿的起源点应位于远离孟氏孔的区域，在这些区域存在一些没有紧密相邻的穹窿结构的解剖学“窗口”。
对有关第三脑室顶部附近结构的解剖变异以及具有类似特征的报道病例的文献进行综述。
胶样囊肿可能通过没有穹窿结构机械限制的解剖学窗口垂直向上生长超过第三脑室顶部。
穹窿结构的一些解剖变异可能使孔后或孔后胶样囊肿出现异常大的尺寸和向上的生长方向。在内镜切除前进行仔细的术前规划并了解这些囊肿的相关病理解剖非常重要，以避免并发症。
