Schwannomas or neurilemmomas are the most often found as solitary, slow-growing, asymptomatic, well-encapsulated, firm yet transversely mobile benign mass in head and neck region. Most of Schwannomas appear in the cranial nerve, especially vestibular nerve, but must always be considered to be able to appear in any parts where the nerve tissues are distributed. Sometimes, inaccurate preoperative clinical diagnosis leads to accidentally resecting the affected nerve and produces permanent neurological deficits. 
We experienced a extremely rare schwannoma being confused with lipoma in upper left postauricular sulcus. After simple mass excision without considering possibility of schwannoma, the patient complained of dull sensation and pinprick pain in the superior part of the ipsilateral postauricular area. 
When clinical symptom and physical examinations are insufficient to distinguish schwannoma from other benign soft masses, and the mass along the critical nerve pathway can possibly be originated from the designated nerves, we would like to recommend radiologic examinations such as ultrasonography and/or MRI for correct diagnosis prior to operation. Moreover, when it is adjacent the neurovascular structures, meticulous microscopic surgery must always be performed so as not to impair the important structures.