Spontaneous Regression of a Large Vestibular Schwannoma: Is Nonoperative Management Reasonable?

Vestibular schwannomas (VSs) are the most common cerebellopontine tumors. The natural history of smaller-sized VSs (<30 mm) has been well-studied, leading to the recommendation of a "watch and wait" approach. However, large VSs (>30 mm) have not been extensively studied, mainly because of their rarity. As such, most patients are conventionally offered surgery which carries a significant risk of neurological morbidity. Here, we report a case of a giant VS (>40 mm) in a 30-year-old man who regressed spontaneously. He was lost to follow-up for 18 years and, upon re-presentation, the symptomatology drastically improved and repeat imaging demonstrated a marked reduction in tumor size. Referring to similar cases in other studies, we postulate that most large and giant VSs undergo a phase of growth and stasis, followed by regression due to shifts in the balance between tumorigenic and regressive factors. Taken together with emerging molecular data, further studies are required to better understand the history of large and giant VSs to shape more personalized treatment options. This potentially includes non-operative management as a tenable option.

Feasibility and safety of a non-operative clinical strategy for radiologically diagnosed low grade anterior mesial temporal tumours in the absence of a histological diagnosis.

BACKGROUND: Although resection of mesial temporal lobe lesions can be achieved with relatively low morbidity, resective surgery is not without risk. Whilst many lesions found in the anterior mesiotemporal lobe are low-grade entities, transforming and high-grade lesions have also been demonstrated. We investigate the feasibility of utilising serial quantitative volumetric imaging, to determine if a strategy of imaging surveillance can be safely employed for the management of radiologically diagnosed anterior mesial temporal low-grade tumours without a confirmed histological diagnosis. METHODS: A retrospective case-note and radiology review design were utilised. The primary presenting symptomatology was recorded together with the efficacy of symptomatic control. Volumetric analysis of MRI images was performed using Brainlab software. Pre- and post-operative neuropsychological data were analysed. RESULTS: 35 patients were identified with a radiological diagnosis of a low-grade anterior mesial temporal lobe tumour. Of these, 29% (n = 10) underwent surgical resection. For the whole cohort, the mean tumour volume at diagnosis was 6.5cm3, with a mean volumetric expansion of 1.4% per month. A significant difference was found between the volumetric expansion rate of those that underwent surgical treatment and those that did not (4.9% per month vs 0.06% per month, p < .01). Of those cases that did not undergo surgical resection, no significant difference was seen between the initial diagnostic volume and the volume at the time of their most recent interval surveillance scan (p = .97). New onset epilepsy was significantly associated with a requirement for eventual surgical tumour resection; relative risk = 6.25, 95% CI = 1.5-25.9, p = .0114. CONCLUSION: Where medical seizure control is adequate, we suggest that conservative management is feasible even in the absence of a confirmed histological diagnosis. However, in patients aged over 50 years with new onset epilepsy, a lower threshold for intervention should be considered.

Diagnostic dilemma in acute neurological presentation of spinal arachnoid cysts: A case report.

Background: Spinal arachnoid cysts are relatively uncommon, cerebrospinal fluid-filled sacs formed by arachnoid membranes that can be either idiopathic or acquired. The neurological presentation of these cysts is varied. Advances in imaging techniques have allowed an improved characterization of these entities and excluded other possible causes of clinical manifestation. Their presentation remains varied, ranging from pain to progressive neurological deficits. Here, we present two cases of patients with thoracic arachnoid cysts that posed a diagnostic dilemma at initial presentation because of their acute neurological deficit, and their eventual recovery after surgical intervention. Case description: The first case is of a patient with end-stage renal failure, which prevented the administration of contrast during the workup. The differential diagnosis ranged from intradural abscess to arachnoid cyst. The second patient presented with non-remitting back pain that progressed to an acute neurological deficit. Both patients recovered well after decompression of the cyst. Conclusion: The decision to intervene is still patient-dependent and based on the extent of neurological deterioration at the time of presentation due to the relatively benign nature and lack of understanding of the temporal presentation of neurological symptoms, which are rapidly and almost completely reversed after surgery. However, further studies need to be done to understand the acute presentation of these cysts, which are apparently long-standing.

Spontaneous obliteration highlights the dynamic nature of cerebral arteriovenous malformations: A case report and review of the literature.

BACKGROUND: Cerebral arteriovenous malformations (AVMs) are dynamic lesions and have been documented to arise de novo, enlarge, regress, obliterate, and even recur. Spontaneous obliteration of AVM is a rare and poorly understood phenomenon. CASE DESCRIPTION: We present a case of spontaneous obliteration of AVM in a 60-year-old gentleman who presented with intraparenchymal hemorrhage from a ruptured right parieto-occipital AVM. Angiography performed before gamma knife surgery 4 months after his initial presentation demonstrated complete absence of AVM. CONCLUSION: In our center's 20-year experience of treatment of cerebral AVMs (approximately 600 cases), this is the only case that has been aborted due to spontaneous obliteration leading us to infer that the incidence of spontaneous AVM obliteration is <1%. Spontaneous obliteration of AVM is a rare but well-established phenomenon that bears testimony to the dynamics of this vascular disorder.