Retroperitoneal cystic schwannoma mimics liquefied hematoma.

Schwannomas are nerve sheath tumors that seldom occur in the retroperitoneal region. Herein, we describe an incidentally detected retroperitoneal schwannoma that mimicked liquefied hematoma on computed tomography. A 61-year-old man was admitted to the emergency department with chest pain caused by a fall at a construction site. Chest computed tomography incidentally revealed a retroperitoneal cystic mass measuring 10 cm, in addition to multiple rib fractures and hemopneumothorax. The patient frequently consumed alcohol and had a history of repeated trauma; therefore, we considered the following 2 conditions: retroperitoneal cystic tumor and liquefied hematoma. He underwent complete surgical excision, and a histopathological examination confirmed the mass as a schwannoma. Experience and knowledge regarding the computed tomography findings of retroperitoneal cystic schwannoma are useful for the differential diagnosis of infrequent retroperitoneal tumors.