Malignant peripheral nerve sheath tumour transformation of histological benign vestibular schwannoma after stereotactic radiosurgery in patients without neurofibromatosis

Abstract

Stereotactic radiosurgery (SRS) poses a minimal but important risk for tumour transformation, typically occurring 8–10 years after the treatment. Malignant peripheral nerve sheath tumour (MPNST) is the most common tumour arising from a vestibular schwannoma treated with SRS, with only 14 cases previously reported. We present the fifteenth case and describe its evolution and clinical course. A 56-year-old man without a history of neurofibromatosis was diagnosed 9 years prior with a vestibular schwannoma. SRS to the residual tumour was given 3 months later. During the current hospitalisation, he was reoperated where histology confirmed a MPNST. All 15 MPNST cases were analysed, showing a 77% female predominance presenting a malignant transformation at a mean age of 51. The diagnosis was made at a mean time of 74 months after SRS. The mean survival time after diagnosis was 16 months. MPNST arising from benign vestibular schwannoma after SRS treatment is an uncommon but devastating complication.

Malignant transformation of vestibular schwannoma after radiation therapy

“…Radiosurgery has emerged as a minimally invasive approach for smaller VSs, offering high tumor control and minimal side effects [4] . However, long-term effects are unclear, with increasing reports of radiation-induced malignancies [7] , [8] , [9] . Our case adds to a series of 24 such cases in the literature, primarily involving MPNSTs in patients with no prior history of neurofibromatosis ( Table 1 ) [8] , [9] , [10] , [11] , [12] , [13] , [14] , [15] , [16] , [17] , [18] , [19] , [20] , [21] , [22] , [23] , [24] , [25] , [26] , [27] , [28] .…”

Malignant Cerebellopontine Angle Peripheral Nerve Sheath Tumor with Divergent Mesenchymal (Cartilaginous) Differentiation Presenting with Catastrophic Hemorrhage: Case Report and Review

“…Management of intracranial MPNST involves multimodal strategies including surgery, radiotherapy, and chemotherapy. 6 Mainstays of treatment include radical surgical resection, adjuvant radiation, and chemotherapy. 3 , 7 Gross total resection is associated with improved disease-specific survival.…”

Stereotactic Radiosurgery for Vestibular Schwannoma in Neurofibromatosis Type 2: An International Multicenter Case Series of Response and Malignant Transformation Risk

“…32,33 In fact, VS malignant transformation or other radiation-induced tumors are exceedingly rare in patients with NF2. 11,12,34,35 When such an event is observed, it may be challenging to establish whether the tumor was radiation-related or a feature of the underlying genetic deletion. Cahan et al 36 proposed standardized criteria to determine whether a tumor was a radiation-induced tumor or an independent new neoplasm in patients with sarcoma.…”

“…[4][5][6][7] The literature presents only a handful of NF2-associated VS malignant transformation case reports with most of the NF2 case series often having short to intermediate follow-up intervals. [8][9][10][11][12] This study relied on multicenter retrospective data from centers who participate in the International Radiosurgery Research Foundation (IRRF). This report examined tumor control, freedom from additional treatment (FFAT), serviceable hearing preservation, and the risk of delayed radiation-related tumor development or malignant transformation of an SRS-treated NF2 VS.…”

“…4-7 The literature presents only a handful of NF2-associated VS malignant transformation case reports with most of the NF2 case series often having short to intermediate follow-up intervals. 8-12…”