Phrenic nerve schwannoma as an incidental intraoperative finding. Case report

INTRODUCTION AND IMPORTANCE: Peripheral neuronal sheath tumors are rare lesions that can arise from the lining of the neuronal axons of any nerve in the body. Schwannomas are usually solitary and encapsulated, slow growing, predominantly benign, with a malignant transformation rate of less than 2% and very low recurrence. The phrenic nerve schwannoma is rare in the neck and usually is asymptomatic. CASE PRESENTATION: We present a case of a phrenic nerve schwannoma as an incidental intraoperative finding in the study of a patient with a cervical mass of progressive growth on the right side of the neck in contact with the anterior scalene muscle and pain intermittent. Resection of the mass was done with preservation of the endoneurium. Intraoperative stimulation after resection had a proper functionality of the phrenic nerve. In the follow-up, the patient had not any damage of the function of the phrenic nerve. CLINICAL DISCUSSION: This tumor is generated by a deficiency of merlin with the consequent cell proliferation. The diagnostic imaging (CT or MRI) are the studies of choice. The differential diagnosis of these lesions has an impact on the presence or absence of oncological disease or progression of a previously treated one. The ideal management is surgical and the anatomical and/or functional preservation of the nerve depend of the tumor infiltration. CONCLUSION: The phrenic nerve schwannoma is rare in the neck. The ideal management is surgical, and this pathology must be considered in patients with masses in the Station IV and supraclavicular fossa of the neck.