Thirty-year clinical experience in gamma knife radiosurgery for trigeminal schwannomas.

We aimed to evaluate the radiographic and clinical outcomes after gamma knife radiosurgery (GKRS) for trigeminal schwannomas (TSs). A total of 87 patients who underwent GKRS for TSs between 1990 and 2020 were enrolled. The mean tumor volume was 4.3 cm3. The median prescribed dose for the margins of the tumor was 13 Gy. The median follow-up duration was 64.3 months (range 12.0-311.5 months). The overall local tumor control rate was 90%, and the symptom response rate was 93%. The response rate for each symptom was 88% for facial pain, 97% for facial sensory change, and 86% for cranial nerve deficits. Nineteen (22%) patients showed transient swelling, which had regressed at the time of the last follow-up. Cystic tumors were associated with transient swelling (p = 0.04). A tumor volume of < 2.7 cm3 was associated with local tumor control in univariable analysis. Transient swelling was associated with symptom control failure in both univariable and multivariable analyses (p = 0.04, odds ratio 14.538). GKRS is an effective treatment for TSs, both for local control and symptom control.

Predictive factors for high-grade transformation in benign meningiomas.

OBJECTIVE: Although they are generally slow-growing benign tumors, meningiomas may recur after surgery with transformation into atypical meningiomas. The purpose of this study was to investigate the radiological and histopathological factors that predict the risk of tumor progression from a benign to an atypical meningioma. PATIENTS AND METHODS: All patients treated for recurrent meningiomas in whom the tumor showed histopathologically confirmed high-grade transformation (HGT) from a benign to an atypical meningioma between 2001 and 2017 were included. To evaluate the predictors of transformation, patient medical records documenting the diagnosis of a benign meningioma at the first surgery prior to second surgery with HGT were reviewed. Each patient was matched with four age- and sex-matched controls who were treated for a benign meningioma. The control group comprised all patients without any recurrence for at least 60 months. RESULTS: Fourteen patients with benign meningioma underwent HGT and were included. The median time interval of transformation was 63 months (range, 19-132 months). Multivariate analysis indicated that an increased mitotic index (odds ratio [OR], 10.409; 95 % confidence interval [CI], 1.297-83.549; P = 0.027) was a significant predictor of transformation. Prominent peritumoral edema (OR, 33.822; 95 % CI, 0.935-223.688; P = 0.054) did not reach the statistical significance. CONCLUSION: An increased mitotic index may be used as the predictor for HGT of benign meningiomas. Although these tumors with a high risk for transformation do not meet the diagnostic criteria for atypical meningiomas, they may require more attentive observation and management than other benign meningiomas.

Growth rate and fate of untreated hemangioblastomas: clinical assessment of the experience of a single institution.

BACKGROUND: The growth rate and natural history of untreated hemangioblastomas remain unclear. This study investigated the natural history of untreated intracranial hemangioblastomas and predictors of tumor growth using volumetric assessment. METHOD: This study retrospectively enrolled 31 patients with untreated hemangioblastomas between 2004 and 2017 who were followed up for at least 12 months. The 31 patients had a total of 52 hemangioblastomas. RESULTS: The 31 patients included 11 (35.5%) men and 20 (64.5%) women, of mean age 42.5 years. Seventeen (54.8%) patients were genetically diagnosed with Von Hippel-Lindau (VHL) disease. Of the 52 lesions, 33 (63.5%) grew during the follow-up period, whereas 19 (36.5%) remained stable. Overall mean actual growth rate (AGR) was 1.94 cm3/year, 2.38 cm3/year in the VHL and 1.79 cm3/year in the non-VHL group (p = 0.31). Overall mean relative growth rate (RGR) was 21%/year, 26%/year in the VHL and 19%/year in the non-VHL group. Time to 50% treatment probability was 34 months. The 1, 3, 5, and 7-year treatment probabilities were 11.5%, 50.1%, 52.7%, and 73%, respectively. The presence of only symptomatic lesions was significantly predictive of the growth of intracranial hemangioblastoma (odds ratio: 5.0, p = 0.02). CONCLUSION: The overall growth rate of intracranial hemangioblastoma was faster than that of other benign intracranial tumors, with symptomatic lesions being the only meaningful predictor of tumor growth. Because of their rapid growth rate and high probability of treatment, a wait and scan management strategy should be carefully applied to intracranial hemangioblastomas.