RESUMO
BACKGROUND: It is known that benign tumors have the potential for malignant transformation. Malignant transformation of vagus nerve schwannoma to angiosarcoma is very rare. METHODS: We report a case of malignant transformation in which the initial diagnosis was subsequently altered to angiosarcoma originating from the vagus nerve. We compared the findings of MRI and fine-needle aspiration (FNA) at initial diagnosis with those after malignant transformation. RESULTS: MRI revealed that the mass property had been changed from the initial tumor; also the FNA findings were significantly different from those in the previous ones. The patient had significant clinical progression with multiple cranial neuropathies and died. CONCLUSION: Schwannomas sometimes undergo malignant transformation; therefore, surgery should be recommended. If follow-up observation is chosen, MRI and FNA should be regular and patients should sign a statement acknowledging awareness of the potential for malignant transformation.