Retroperitoneal teratoma misdiagnosed as a gastric stromal tumor: A case report.

The misdiagnosis of retroperitoneal teratoma as a gastric stromal tumor is rarely reported. There are numerous abdominal organs, and retroperitoneal tumors are easily concealed by organs situated more anteriorly on the abdomen; therefore, retroperitoneal tumors are easily misdiagnosed as human digestive system tumors by abdominal surgeons. We herein present the case of a 39-year-old female patient who was diagnosed with a gastric stromal tumor (GST) on preoperative examination, whereas the postoperative diagnosis was retroperitoneal mature cystic teratoma. Such cases are clinically rare. In the present case, the tumor was located in the retroperitoneum, near the lesser gastric curvature, without an obvious gap. The anterior surface of the tumor was concealed by the lesser gastric curvature and did not move significantly with breathing and changes in posture. In such cases, a preoperative misdiagnosis is very likely. The aim of the present study was to improve our understanding of the presentation of retroperitoneal teratomas, thereby gaining more clinical experience and hopefully reducing the rate of misdiagnosis.