Preoperative anticipation of origin from MRI scans in cervical phrenic schwannoma.

Schwannomas of the head and neck are uncommon tumors that arise from any peripheral, cranial or autonomic nerve. We report the usefulness of MRI scans when expecting the origin of schwannoma to be phrenic nerve. We present a case of a 56-year-old woman with an enlarging right-sided neck mass. There was no neurological symptom. The examinations showed no abnormalities except neck ultrasonography, CT and MRI scans. From the MRI scans, we hypothesized a phrenic nerve origin preoperatively, based on the association of the mass with the C3 vertebra. We performed a total excision, sacrificing the phrenic nerve. The pathological examination showed an Antoni A type schwannoma. Postoperatively, the right diaphragm was elevated without any respiratory disorders. We could consider the possibility of phrenic nerve or cervical plexus involvement based on the relationship of the mass to an interbody as seen with MRI.