[A Case of Retroperitoneal Cavernous Hemangioma Difficult to Differentiate from Retroperitoneal Liposarcoma].

We report a case of retroperitoneal cavernous hemangioma. A 77-year-old woman complaining of nausea was admitted to a different hospital in September 2013. Computed tomography (CT) detected a retroperitoneal mass in the left pararenal space. Three years later, repeated CT showed that the tumor had gradually grown in size. On dynamic contrast-enhanced magnetic resonance imaging (MRI), the tumor demonstrated radiographic signs of a liposarcoma. Resection of the mass with left nephrectomy was performed in June 2016, and histopathology showed cavernous hemangioma. Clinical diagnosis of cavernous hemangioma is difficult, and imaging modalities, including CT and MRI, may not be conclusive. The final diagnosis in most cases is established through surgery. This is the 29th case of retroperitoneal cavernous hemangioma to be reported in Japan.