Case of malignant transformation of vagus nerve schwannoma to angiosarcoma.

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.