Incidental discovery of acoustic neuromas

Evolution in the management of vestibular schwannoma: a single-center 15-year experience

PURPOSE

To highlight the changes in the management of vestibular schwannoma (VS) since 2004 with a focus on small- to middle-size VS.

METHODS

Retrospective analysis of the decisions made in skull base tumor board between 2004 and 2021.

RESULTS

1819 decisions were analyzed (average age 59.25, 54% females). Overall, 850 (47%) cases were allocated to a Wait and Scan (WS) approach, 416 (23%) received radiotherapy and 553 (30%) were treated surgically (MS). All stages considered WS increased from 39% before 2010 to 50% after 2010. Similarly, Stereotactic Radio Therapy (SRT) increased from 5 to 18%. MS decreased from 46 to 25%. It was more commonly proposed to younger patients and larger tumors, p < 0.001. For Koos stages 1, 2, and 3 there was a statistically significant increase in SRT, and a decrease in MS, p < 0.001. WS also increased for stages 1 and 2. However, such a trend was not observed for stage 3. MS remained the primary treatment modality for stage 4 tumors throughout the study period, p = 0.057. The significance of advanced age as a factor favoring SRT decreased over time. The opposite is true for serviceable hearing. There was also a decrease in the percentage of the justification "young age" in the MS category.

CONCLUSION

The is a continuing trend towards non-surgical treatment. Small- to medium-sized VS witnessed an increase in both WS and SRT. There is only an increase in SRT for moderately large VS. Physicians are less and less considering young age as a factor favoring MS over SRT. There is a tendency towards favoring SRT when hearing is serviceable.

Magnetic Resonance Imaging-Based Screening for Asymptomatic Brain Tumors: A Review

Brain tumors comprise 2% of all cancers but are disproportionately responsible for cancer-related deaths. The 5-year survival rate of glioblastoma, the most common form of malignant brain tumor, is only 4.7%, and the overall 5-year survival rate for any brain tumor is 34.4%. In light of the generally poor clinical outcomes associated with these malignancies, there has been interest in the concept of brain tumor screening through magnetic resonance imaging. Here, we will provide a general overview of the screening principles and brain tumor epidemiology, then highlight the major studies examining brain tumor prevalence in asymptomatic populations in order to assess the potential benefits and drawbacks of screening for brain tumors. IMPLICATIONS FOR PRACTICE: Magnetic resonance imaging (MRI) screening in healthy asymptomatic adults can detect both early gliomas and other benign central nervous system abnormalities. Further research is needed to determine whether MRI will improve overall morbidity and mortality for the screened populations and make screening a worthwhile endeavor.

The approach to the patient with incidentally diagnosed vestibular schwannoma

With the increasing prevalence and decreasing cost of MRI scans, incidental discovery of vestibular schwannoma (VS) has become more common. Scarce literature exists regarding management of the tumors in those patients with incidentally discovered VSs, and clear guidelines for management do not exist. In this review, the authors examine the available literature for insights into management of incidentally diagnosed VS and provide an algorithm for their management.

Incidental vestibular schwannomas: a review of prevalence, growth rate, and management challenges

With the relatively recent increase in the use of MRI techniques, there has been a concurrent rise in the number of vestibular schwannomas (VSs) detected as incidental findings. These incidental VSs may be prevalent in up to 0.02%–0.07% of individuals undergoing MRI and represent a significant portion of all diagnosed VSs. The management of these lesions poses a significant challenge for practitioners. Most incidental VSs tend to be small and associated with minimal symptoms, permitting them to be managed conservatively at the time of diagnosis. However, relatively few indicators consistently predict tumor growth and patient outcomes. Furthermore, growth rates have been shown to vary significantly over time with a large variety of long-term growth patterns. Thus, early MRI screening for continued tumor growth followed by repeated MRI studies and clinical assessments throughout the patient's life is an essential component in a conservative management strategy. Note that tumor growth is typically associated with a worsening of symptoms in patients who undergo conservative management, and many of these symptoms have been shown to significantly impact the patient's quality of life. Specific indications for the termination of conservative management vary across studies, but secondary intervention has been shown to be a relatively safe option in most patients with progressive disease. Patients with incidental VSs will probably qualify for a course of conservative management at diagnosis, and regular imaging combined with the expectation that the tumor and symptoms may change at any interval is crucial to ensuring positive long-term outcomes in these patients. In this report, the authors discuss the current literature pertaining to the prevalence of incidental VSs and various considerations in the management of these lesions. It is hoped that by incorporating an understanding of tumor growth, patient outcomes, and management strategies, practitioners will be able to effectively address this challenging disease entity.

The prevalence and clinical course of patients with 'incidental' acoustic neuromas

CONCLUSIONS

This study suggests that among patients diagnosed with 'incidental' acoustic neuromas (ANs), a substantial portion are discovered incidentally. Small and medium-sized ANs that are found incidentally may have a more benign nature, and may be less likely to require interventions.

OBJECTIVE

To estimate the prevalence of ANs, and to compare the prognosis and progression of the disease between those diagnosed incidentally verse symptomatically with an AN.

PATIENTS AND METHODS

This was a retrospective evidence-based case series of patients with AN treated at a tertiary medical center between November 1999 and January 2005. An MRI with gadolinium was performed on all patients to establish the diagnosis of AN. A medical chart review of these patients was searched for sex distribution, age, presenting symptoms, hearing loss, speech discrimination scores, tumor characteristics by imaging, intervention performed, and time between diagnosis and intervention. The studied population was divided into those patients with pre-imaging audiovestibular symptoms provoking a clinical suspicion of AN (symptomatic group) and those without a pre-imaging suspicion of AN (incidental group).

RESULTS

The charts of 120 patients with ANs were analyzed and categorized as either incidentally or symptomatically discovered. Incidentally discovered ANs accounted for 12% of patients with the diagnosis of AN in our population. The average age at diagnosis was 55.7 and 52.8 years (p = 0.50) in the symptomatic and incidental groups, respectively. The gender distribution was not different between the groups (p = 0.08). Audiometry revealed a speech discrimination score asymmetry greater in the symptomatic group (p < 0.0001). Tumor size by imaging performed at diagnosis in the incidental population was 1.09 cm on average, compared with 1.5 cm in the symptomatic patients (p = 0.08). A greater proportion of patients with symptomatically discovered AN underwent intervention by surgical resection, stereotactic radiosurgery, or radiation compared with patients with incidentally discovered AN (76% versus 47%, p = 0.02).

Differentiation between cerebellopontine angle tumors in cancer patients

OBJECTIVE

The possibility of metastasis to the cerebellopontine angle should be considered when a cancer patient has inner ear-related symptoms, although such metastasis is rare. Distinguishing between an independent tumor and a metastasis presents a challenge to the clinician once magnetic resonance imaging reveals a space-occupying lesion in the cerebellopontine angle. This study attempted to differentiate between primary benign and metastatic malignant cerebellopontine angle tumors in cancer patients.

SETTING

University hospital.

PATIENTS

A total of 174 cancer patients with inner ear-related symptoms such as vertigo, hearing loss, or tinnitus were seen at the university hospital from January 1994 to December 2000. All patients underwent a battery of audiologic and neurotologic tests. Magnetic resonance imaging was performed either when the clinical presentation suggested vertigo of central origin or when sensorineural hearing loss developed.

RESULTS

Magnetic resonance imaging confirmed tumors of the cerebellopontine angle in 6 (3%) of the 174 patients, including 3 men and 3 women. Their ages ranged from 46 to 80 years (mean 62 years). The final diagnoses were breast cancer with cerebellopontine angle metastasis (1), breast cancer with cerebellopontine angle epidermoid cyst (1), colon cancer with cerebellopontine angle metastasis (1), colon cancer with acoustic neuroma (1), nasopharyngeal carcinoma with cerebellopontine angle metastasis (1), and nasopharyngeal carcinoma with cerebellopontine angle benign tumor (1).

CONCLUSIONS

When a cerebellopontine angle tumor is discovered in a cancer patient, metastatic cancer should be suspected when the tumor presents with deficits of the VIIth and VIIIth cranial nerves of rapid progression or bilateral involvement, or extracranial systemic metastasis. Laboratory examinations such as cytologic study of the cerebrospinal fluid and serologic study can assist in the diagnosis.

Predicting the stability and growth of acoustic neuromas

HYPOTHESIS

Acoustic neuroma (AN) growth can be predicted using information gathered at the time the AN is initially diagnosed.

BACKGROUND

Knowledge of AN growth is essential for treatment planning. Previous studies have not been able to identify predictors of AN growth.

METHODS

A multivariate statistical analysis was carried out using two independent sets of secondary data from the natural histories of ANs. Logit, probit, and censored regression techniques were used to test alternative hypotheses of AN growth between the initial and second measurements, as well as between subsequent measurements.

RESULTS

In one data set, AN growth between the first and second measurements varied significantly and inversely with age. It was much greater if the AN was on the left side and if there were more symptoms. It did not depend on initial tumor size or the measurement interval. In the other data set, AN growth was also greater for left-sided tumors and depended on symptoms. However, it varied inversely with tumor size and directly with the measurement interval. There was also some evidence that tumors that were more stable between the initial two measurements were more likely to remain stable between the second and third measurements. However, this did not apply to AN growth between the third and fourth measurements.

CONCLUSIONS

AN growth is predictable but the prediction model is not apparently independent of the policy for selecting ANs for conservative management.

[Asymptomatic acoustic neurinoma associated with hypophyseal macroadenoma]

The widespread use of gadolinium-enhanced MRI (Gd-MRI) in our hospitals has supposed an increase in detection of asymptomatic acoustic neuromas (AN) as incidental finding. Concurrent primary intracranial tumors of different cell types are extremely uncommon.

CLINICAL CASE

A 23 year-old woman complained of irregular menstrual cycles and galactorrhea for two years. A Gd-MRI scan showed a pituitary macroadenoma and an AN of 1.4 cm. with intracanalicular and cisternal extension. The patient did not have any otologic or neuro-otologic symptoms or signs. Audiograms revealed bilateral normal hearing. The results of acoustic reflex test and electronystagmographic caloric tests were normal. The AN underwent radiosurgery treatment.

DISCUSSION

The literature about atypical AN is reviewed, giving a particular concern on asymptomatic cases. We only have found one case of association between AN and pituitary adenoma. The real prevalence of AN in general population is discussed.

[Magnetic resonance: first choice test in the screening of internal auditory canal and cerebellopontine angle tumors]

Although internal auditory canal (IAC) and cerebellopontine angle (CPA) tumors are rare, their clinical suspicion is quite common in the otolaryngology office. MRI is the imaging modality of choice in diagnosing these tumors. Perceived high costs may prevent clinicians from using it as a screening tool. A protocol designed to improve cost-effectiveness in such diagnosis results in a more rationale clinical practice. Our aim was to evaluate the usefulness of MRI as screening tool in diagnosis of IAC and CPA tumors in our population. Between March 1998 and March 2000, a prospective series of 200 cases had a MRI screening requested. MRI were performed following Fast Spin Echo technique, providing T2-weighted images. Gadolinium enhanced MRI was reserved for selected cases. We report on 190 MRI done. We found 7 neuromas (3.5%), one CPA metastasis, one epidermoid cyst and 9 IAC vascular anomalies. Only 138 cases (69%) had normal MRI images. When used following a designed protocol, MRI is our procedure of choice while screening IAC and CPA tumors because it is a cost-effective tool.