AP-HP, Department of Otology, auditory implants and skull base surgery, Hôpital Pitié-Salpêtrière, France.
Sorbonne Universités, Inserm, Minimally invasive and robot-based surgical rehabilitation of hearing, Paris, France.
PLoS One. 2019 Jun 4;14(6):e0217752. doi: 10.1371/journal.pone.0217752. eCollection 2019.
The natural history of sporadic vestibular schwannoma is unpredictable, with tumors growing, non-growing and even showing spontaneous regression in some rare cases.
This retrospective study aims to describe the radiologic signs characterizing and identifying the shrinking vestibular schwannoma.
Involution was considered to have occurred if tumor size had decreased by 2 mm or more on its largest diameter. All magnetic resonance imaging scans were reviewed for tumor size, internal auditory meatus size, and tumor characteristics. Volumetric measurements were performed on the first and last scan. Audiometric data were collected at the first and last visit.
Fourteen patients with a confirmed spontaneous regression were included, with a mean follow-up of 5 ± 2.6 years. The mean shrinkage rate was 0.9 ± 0.59 mm/year on 2D measurements, and 0.2 ± 0.17 cm3/year on volumetric measurements, with a relative shrinkage of 40 ± 16.9%. Two remarkable radiologic features were observed: First, a festooned aspect, defined by multiple curves in the tumor outline, noticed in 12 cases (86%); second, the appearance of cerebrospinal fluid filling the internal auditory meatus, associated with an enlargement of the internal auditory meatus compared to the contralateral side, and observed in 10 out of 13 cases with internal auditory meatus invasion (77%). Those two aspects were associated in 64% of cases.
These two newly reported radiologic features could help neurosurgeons, oto-neurosurgeons and neuroradiologists to identify a spontaneous vestibular schwannoma involution at first visit. This could allow any treatment to be postponed, monitoring to be more widely spaced, and patients to be reassured.
散发性前庭神经鞘瘤的自然病程不可预测，有些罕见病例肿瘤会生长、不生长甚至出现自发消退。
本回顾性研究旨在描述特征性的影像学表现，以识别缩小的前庭神经鞘瘤。
如果肿瘤最大直径缩小 2 毫米或以上，则认为发生了退缩。所有磁共振成像扫描均用于评估肿瘤大小、内听道大小和肿瘤特征。对首次和末次扫描进行肿瘤体积测量。收集首次和末次就诊时的听力数据。
纳入 14 例经证实的自发消退患者，平均随访 5±2.6 年。二维测量的平均退缩率为 0.9±0.59 毫米/年，体积测量的平均退缩率为 0.2±0.17 立方厘米/年，相对退缩率为 40±16.9%。观察到两个显著的影像学特征：首先，在 12 例（86%）中观察到肿瘤轮廓呈多曲线的“花边状”外观；其次，在 13 例内听道侵犯（77%）中观察到脑脊液填充内听道，伴同侧内听道扩大。这两个方面在 64%的病例中同时存在。
这两个新报道的影像学特征有助于神经外科医生、耳神经外科医生和神经放射科医生在首次就诊时识别自发性前庭神经鞘瘤退缩。这可以延迟任何治疗，更广泛地间隔监测，并使患者安心。
