Spindle cell type malignant peripheral nerve sheath tumor arising in benign schwannoma with multiple intraosseous spinal metastasis: A case report.

Abstract

Malignant peripheral nerve sheath tumor (MPNST) arising in benign schwannoma with multiple intraosseous spinal metastasis is extremely rare, having a highly aggressive progression and poor prognosis. In such cases, the malignant cells of MPNST usually have an epithelioid morphology. Here, the authors present a very rare case of spindle cell type MPNST arising in benign schwannoma. A 47-year-old woman had a history of wide marginal excision of right buttock spindle cell sarcoma previously. However, metastatic lesions to C7, L1 body, and the right lung were detected during follow-up. Total spondylectomy and stabilization of the C7 and L1 tumors were performed within an interval of 5 months. However, the patient expired 6 months after the last surgery. From analysis and study of three tumor specimens (right buttock, cervical and lumbar spine), the pathological diagnosis based on histomorphologic and immunohistochemical studies was spindle cell sarcoma, high grade, most consistent with MPNST arising in schwannoma. It is important that pathologists and surgeons recognize that spindle cell type MPNST may arise in benign schwannoma, as this recognition aids in assessment of patients with schwannoma and contributes to the pathologist making a more precise diagnosis, and the surgeon better determining the appropriate therapeutic options and surgical methods.