Recent Advances in the Management of Atypical Meningioma

We reviewed the literature for specific features characterizing atypical meningiomas. Recent advances in the field of therapeutic strategies and management was also analyzed. Meningiomas are the most common primary intracranial neoplasms. Following the 2007 WHO classification, which included all brain invasive meningiomas as grade II, the proportion of atypical meningiomas has steeply increased to up to 35%¹ of all meningiomas. Genetic profiling has shown that several accumulated genetic alterations and allelic imbalances were correlated with the histopathologic classification (Fig. 1). In a radiographic standpoint, magnetic resonance imaging's spectral features help distinguish the aggressive nature of meningiomas (Table 1). Complete resection is usually considered curative when benign; however, the recurrence rate is not negligible in atypical meningiomas and it is estimated at ∼41%² In this regard, adjuvant therapies like radiotherapy, administered as conventional external beam irradiation or stereotactic radiosurgery, has been strongly recommended after subtotal resection. In gross total resection, however, both close observation and early adjuvant radiation can be advocated.³ Chemotherapy has been used mainly for refractory cases. Recent studies have given limited results.⁴ The search continues for newer chemotherapeutic agents or for a combination of existing agents, particularly for recurrence of disease following surgery and radiotherapy, and Sunitinib may open the way toward new therapeutic options. Management of atypical meningioma remains challenging to the treating physician. Surgery remains the mainstay of primary management, and adjuvant therapy has proven to be required often. An ongoing randomized controlled study is hoping to give higher evidence of this practice (phase III “ROAM/EORTC N° 1308” trial).

Fig. 1 Genetic cascade.

Table 1 Summary of radiological features differentiating histological grade

Radiological feature	Prediction of aggressive histology
Peritumoral edema	NO
Mushrooming/lobulations	YES
Lower ADC values	YES
Increased CBV	Trend to YES
Nonenhancing rim pattern	YES
Hyperostosis/bone destruction	NO
Extracranial extension	YES
Necrotic/cystic zones	Contrasting results
Arterial encasement	NO
Low N-aspartate peak	YES
High Cho/Cr ratio	YES

References

References

1 Claus EB, Bondy ML, Schildkraut JM, Wiemels JL, Wrensch M, Black PM. Epidemiology of intracranial meningioma. Neurosurgery 2005;57(6):1088–1095, discussion 1088–1095

2 Aghi MK, Carter BS, Cosgrove GR, et al. Long-term recurrence rates of atypical meningiomas after gross total resection with or without postoperative adjuvant radiation. Neurosurgery 2009;64(1):56–60, discussion 60

3 Jenkinson MD, Weber DC, Haylock BJ, Mallucci CL, Zakaria R, Javadpour M. Atypical meningoma: current management dilemmas and prospective clinical trials. J Neurooncol 2015;121(1):1–7

4 Moazzam AA, Wagle N, Zada G. Recent developments in chemotherapy for meningiomas: a review. Neurosurg Focus 2013;35(6):E18