No Evidence of Recurrent Vestibular Schwannoma
Based on this MRI report showing no enhancement within the internal auditory canal or cerebellopontine angle cistern, there is no evidence of recurrent vestibular schwannoma, and the patient should continue routine surveillance imaging. 1, 2
Interpretation of Current Imaging Findings
The key radiologic finding that excludes recurrence is the absence of enhancement within the internal auditory canal or CP angle cistern on this non-contrast MRI. 3 While this study was performed without intravenous contrast, the report explicitly states no enhancement is present, suggesting either the radiologist reviewed prior contrast studies or used inherent signal characteristics to make this determination.
Post-Operative Changes Are Expected
- The right temporal bone post-operative changes with wall-up mastoidectomy and residual mastoid air cell fluid are consistent with expected surgical changes following translabyrinthine or retrosigmoid approach. 4, 5
- Decreased mastoid air cell fluid compared to prior imaging actually suggests normal post-operative evolution rather than concerning pathology. 5
Surveillance Strategy Moving Forward
For patients with gross total resection of vestibular schwannoma, MRI should be performed at 2,5, and 10 years post-operatively. 1, 2 The timing of this current study relative to the original surgery determines the next imaging interval:
- If this represents the 2-year post-operative scan and shows no linear or nodular enhancement, the next MRI should be at 5 years post-surgery. 5, 6
- If linear enhancement of the IAC is present at 2 years (which this report does not indicate), repeat imaging at 5 years is needed, as all such cases in one series showed no progression. 5
- Nodular enhancement would indicate definite recurrence requiring intervention, but this is not present in your patient. 3, 5
Evidence Supporting This Surveillance Approach
- A study of 314 patients who underwent complete translabyrinthine VS excision found that all patients with no recurrence at 2 years also had no signs of recurrence at 5 years. 5
- Another series of 91 patients with mean 11-year follow-up after translabyrinthine approach showed zero recurrences after total removal. 6
- The American Academy of Neurology recommends annual MRI for 5 years after incomplete resection, but for gross total resection, imaging at 2,5, and 10 years is sufficient. 1
Critical Distinction: Linear vs. Nodular Enhancement
- Linear enhancement along the IAC is often benign post-operative change that can persist beyond 6 months and does not necessarily indicate recurrence. 3, 5
- Nodular enhancement is highly suspicious for recurrent tumor and requires intervention. 3, 5
- Your patient's imaging shows neither pattern, which is reassuring. 3
Recurrence Risk Context
The recurrence risk depends entirely on the completeness of original resection:
- Gross total resection: 3.8% recurrence rate 2
- Near-total resection: 9.4% recurrence rate 2
- Subtotal resection: 27.6% recurrence rate 2
Mean time to recurrence is 22 months (range 6-143 months), so continued surveillance remains important even with negative current imaging. 2
Management If Future Recurrence Develops
- For vestibular schwannomas recurring after surgery, stereotactic radiosurgery should be used preferentially because the risk of facial nerve damage is lower than with a second operation. 7
- Salvage surgery after prior resection is more difficult and associated with increased likelihood of subtotal resection and decreased facial nerve function. 1
- Radiosurgery using doses of 11-14 Gy provides superior facial nerve and hearing preservation compared to reoperation. 7
Incidental Finding Requiring Attention
The moderate mucosal thickening throughout the ethmoid air cells and left maxillary sinus described as chronic paranasal sinus disease is unrelated to the vestibular schwannoma but may warrant otolaryngologic evaluation if the patient is symptomatic. 3