Multiple primary pulmonary meningiomas: 20-year follow-up findings for a first reported case confirming a benign biological nature

IntroductionPrimary pulmonary meningiomas (PPMs) are very rare neoplasms, and we reported the first multiple case of PPMs in 1998. Usually, PPMs are slow-growing tumors with a good prognosis. Herein, we reported a rare multiple case of PPMs with an extremely long clinical course.Presentation of the caseAn 84-year-old Japanese woman with a history of multiple PPMs histologically confirmed as having a right-sided slowly growing lung nodule for 20 years. In 2010, we also reported the additional clinical course in the initial case 10 years after surgery implying a benign biological nature. Subsequent to that report, new lesions appeared in the bilateral lung fields with quite a slow growth rate. She was asymptomatic, and no tumor was observed in the cranial cavity during the course of her disease.Discussion and conclusionThis case illustrates rare multiple PPMs and highlights their biological behavior with very slow progression from a most likely benign tumor over a 20-year period.     

Adjuvant radiotherapy for atypical and malignant meningiomas: a systematic review

Atypical meningiomas (AMs) and malignant meningiomas (MMs) are tumors with a lower incidence and poorer prognosis than benign meningiomas. The role of radiotherapy as an adjuvant to surgical resection, especially for AMs, is incompletely defined. In this study, the English-language literature was systematically reviewed for studies that reported tumor characteristics, treatment parameters, and clinical outcomes after adjuvant radiotherapy for AM and MM, including overall survival, progression-free survival, and/or time to recurrence or mortality. Clinical outcomes were further assessed in the context of resection status, timing of administration, and radiation dose. Outcomes after stereotactic radiosurgery were also examined. Treatment toxicity and other potential prognostic or confounding factors were appraised. Ten and 11 studies for AM and MM, respectively, met the inclusion criteria. The median 5-year progression-free survival and overall survival after adjuvant radiotherapy were 54.2% and 67.5%, respectively, for AM and 48% and 55.6% for MM. The complication rates were 11.1% for AM and 5.1% for MM. Incomplete resection and radiation dose <50 Gy conferred significantly poorer 5-year progression-free survival. Most studies were unable to demonstrate a statistically significant prognostic benefit for adjuvant radiotherapy in AM. In conclusion, adjuvant radiotherapy significantly improved local control of AMs and MMs, especially after subtotal resection. Study limitations, including inadequate statistical power, may underlie the studies'' inability to demonstrate a statistically significant benefit for adjuvant radiotherapy in AM. Because these tumors preferentially recur within 5 years of surgical resection, future studies should define whether early adjuvant therapy should become part of the standard treatment paradigm for completely excised tumors.     

Glucose and methionine uptake and proliferative activity in meningiomas

Abstract

Despite similar benign histological appearances, proliferative activity of meningiomas varies tumor to tumor, and even region to region in a tumor. To predict proliferative potential before surgery, we compared regional uptake of2-[18F]fluoro-2-deoxyglucose ([18F]FDC) and L-fmethyl-11 CJmethionine ([71C]MET) with histological indices of tumor proliferative activity in 17 specimens from six patients with meningioma obtained by PET guided stereotactic biopsies. Uptake of I11C]MET', an index of protein synthesis rate, significantly correlated not only with the count of nucleolar organizer regions (NORs), a histological index of protein synthesis, but also with Ki-67 index, a histological index of proliferative activity. On the other hand, [18F]FDC uptake showed no significant correlation with Ki-67 index or clinical malignancy. These results suggest that [11 C]MET-PET is a useful tool for predicting tumor proliferative potential in meningiomas. [Neurol Res 1999; 21: 640-644]     

Investigation of blood flow in meningothelial and fibrous meningiomas by xenon-enhanced CT scanning

Abstract

We investigated whether xenon-enhanced computed tomography was able to separate meningothelial meningioma from fibrous meningioma. Cerebral blood flow was studied by xenon-enhanced computed tomography in six patients with incidentally detected intracranial meningiomas. All of the tumors were small (<32mm) and there was little or no péritumoral edema. Three patients had meningothelial meningioma and three patients had fibrous meningioma. The tumor blood flow and the contralateral tissue blood flow were determined. The ratio of these parameters was 7.753 ± 0.467 for meningothelial meningiomas and 0.809±0.105 for fibrous meningiomas, with a significant difference between the two tumor subtypes (p = 0.0185). There was no correlation between the signal intensity on magnetic resonance imaging and tumor subtype, and the findings on cerebral angiography also did not indicate the subtype. In conclusion, xenon-enhanced computed tomography showed a difference between smaller meningothelial and fibrous meningiomas in patients with normal surrounding brain tissue. We could not confirm that xenon-enhanced computed tomography was able to distinguish the subtype of meningioma because of the small number of subjects in this study, but our findings might expand interest in the clinical use of this method. [Neurol Res 2000; 22: 615-619]     

Mitotic Index is an Independent Predictor of Recurrence‐Free Survival in Meningioma

While World Health Organization (WHO) grading of meningioma stratifies patients according to recurrence risk overall, there is substantial within‐grade heterogeneity with respect to recurrence‐free survival (RFS). Most meningiomas are graded according to mitotic counts per unit area on hematoxylin and eosin sections, a method potentially confounded by tumor cellularity, as well as potential limitations of accurate mitotic figure detection on routine histology. To refine mitotic figure assessment, we evaluated 363 meningiomas with phospho‐histone H3 (Ser10) and determined the mitotic index (number of mitoses per 1000 tumor cells). The median mitotic indices among WHO grade I (n = 268), grade II (n = 84) and grade III (n = 11) tumors were 1, 4 and 12. Classification and regression tree analysis to categorize cut‐offs identified three subgroups defined by mitotic indices of 0–2, 3–4 and ≥5, which on univariate analysis were associated with RFS (P < 0.01). In multivariate analysis, mitotic index subgrouped in this manner was significantly associated with RFS (P < 0.01) after adjustment for Simpson grade, WHO grade and MIB‐1 index. Mitotic index was then examined within individual WHO grade, showing that for grade I and grade II meningiomas, mitotic index can add additional information to RFS risk. The results suggest that the use of a robust mitotic marker in meningioma could refine risk stratification.     

Piezosurgery for safe and efficient petrous bone cutting in cerebellopontine angle and petroclival meningioma surgery

Intradural petrous bone drilling has become a widespread practice, providing extended exposure in the removal of cerebellopontine angle (CPA) or petroclival tumors. Adjacent neurovascular structures are at risk, however, when drilling is performed in this deep and narrow area. Hence, this study evaluates the use of Piezosurgery (PS) as a non-rotating tool for selective bone cutting in CPA surgery.A Piezosurgery® device was used in 36 patients who underwent microsurgery for extra-axial CPA or petroclival tumors in our Neurosurgical Department between 2013 and 2019. The clinical and radiological data were retrospectively analyzed. The use of PS was evaluated with respect to the intraoperative applicability and limitations as well as efficacy and safety of the procedure.Piezosurgical petrous bone cutting was successfully performed in the removal of meningiomas or extra-axial metastases arising from the dura of the petroclival region (21 patients) or petrous bone (15 patients). PS proved to be very helpful in the deep and narrow CPA region, considerably reducing the surgeon’s distress toward bone removal in close proximity to cranial nerves and vessels in comparison to common rotating drills. The use of PS was safe without injuries to neurovascular structures. Gross total resection was achieved in 67% of petroclival and 100% of petrous bone tumors.Piezosurgery proved to be an effective and safe method for selective petrous bone cutting in CPA surgery avoiding rotating power and associated risks. This technique can particularly be recommended for bone cutting in close vicinity to critical neurovascular structures.