Talacchi A, Sala F, Alessandrini F, Turazzi S, Bricolo A
Department of Neurological Sciences and Vision, Verona University Hospital, Italy.
Neurosurgery. 1998 Feb;42(2):242-51; discussion 251-2. doi: 10.1097/00006123-199802000-00020.
The management of a series of 28 patients operated on for posterior fossa epidermoids is reviewed, emphasizing the need for long-term follow-up. We discuss the rationale for a comprehensive classification system that may allow the comparison of results from homogeneous series.
We grouped the tumors to differentiate the surgical management according to various tumor sites and the degree of extension. Twenty patients harbored tumors located in the cerebellopontine angle, five patients harbored tumors in the fourth ventricle, and three patients harbored tumors in the posterior fossa basal. In 17 patients, extensions of tumors outside the posterior fossa included the following regions: the suprasellar/ chiasmatic (n = 5), the parasellar/temporobasal (n = 5), and the mesencephalic/pineal (n = 7). Tumor extension was also defined by the number of regions involved. Pre- and postoperative magnetic resonance imaging and computed tomographic findings collected in 17 and 28 patients, respectively, were carefully evaluated.
Clinical features and surgical approaches varied according to location and growth pattern. Fifty-seven percent of the tumors were completely removed. A higher total removal rate was achieved in patients with tumors confined to the primary location. One patient (3%) died in the perioperative period. Approximately half of the patients presented with transient mild focal deficit impairments resulting from the manipulation of the nervous structure over a wide area. There was a higher rate of surgical complications with fourth ventricle and mesencephalic extended cerebellopontine angle tumors. The mean follow-up period was 8.6 years. Thirty percent of the patients with subtotal removal experienced symptomatic recurrences after 8.1 years, whereas all patients with total removal were still asymptomatic. The recurrence-free survival rate was 95% at 13 years for patients with total removal compared with 65% for patients with subtotal removal. Problems of identification of tumor regrowth are discussed.
By assessing posterior fossa epidermoids, we determined that location and extension play a major role in the prognosis. Our data suggest that more aggressive surgery is called for at first operation, and that a second operation should be planned when regrowth becomes symptomatic and/or tends to extend outside its original site.
回顾28例接受后颅窝表皮样囊肿手术患者的治疗情况，强调长期随访的必要性。我们讨论了一个全面分类系统的基本原理，该系统可能有助于比较同类病例系列的结果。
我们根据肿瘤的不同部位和扩展程度对肿瘤进行分组，以区分手术治疗方式。20例患者的肿瘤位于桥小脑角，5例患者的肿瘤位于第四脑室，3例患者的肿瘤位于后颅窝底部。17例患者的肿瘤扩展至后颅窝以外的区域，包括：鞍上/视交叉区（n = 5）、鞍旁/颞底部（n = 5）和中脑/松果体区（n = 7）。肿瘤扩展情况也根据累及区域的数量来定义。分别对17例和28例患者术前和术后的磁共振成像及计算机断层扫描结果进行了仔细评估。
临床特征和手术方式因肿瘤位置和生长模式而异。57%的肿瘤被完全切除。局限于原发部位的肿瘤患者实现了更高的全切率。1例患者（3%）在围手术期死亡。约一半的患者因广泛的神经结构操作出现短暂性轻度局灶性功能缺损。第四脑室和中脑扩展至桥小脑角的肿瘤手术并发症发生率更高。平均随访期为8.6年。次全切患者中有30%在8.1年后出现症状性复发，而所有全切患者仍无症状。全切患者13年的无复发生存率为95%，次全切患者为65%。讨论了肿瘤复发识别的问题。
通过评估后颅窝表皮样囊肿，我们确定位置和扩展程度对预后起主要作用。我们的数据表明，初次手术时应采取更积极的手术方式，当肿瘤复发出现症状和/或倾向于扩展至原发部位以外时，应计划进行二次手术。
