A 68-Year-Old Woman Presenting with Recurrent Abdominal Pain and a Diagnosis of a Presacral Retroperitoneal Benign Schwannoma that Mimicked an Ovarian Tumor on Pelvic Magnetic Resonance Imagining.

BACKGROUND Schwannomas are benign tumors and their appearance in the pelvic region is rare and poses a major diagnostic problem. They can be sporadic or associated with genetical syndromes. They have a slow growth rate and may be asymptomatic for many years. Symptoms are usually nonspecific and due to compression of adjacent structures. Abdominal imaging modalities may not be able to differentiate a benign schwannoma from a malignant retroperitoneal tumor. This report is of a case of a 68-year-old woman presenting with recurrent abdominal pain and a diagnosis of a presacral retroperitoneal benign schwannoma that mimicked an ovarian tumor on pelvic magnetic resonance imaging. CASE REPORT The patient had a history of a femoral hernia repair and recurrent lower abdominal pain. Pelvic imaging raised the suspicion of a primary ovarian tumor. The mass appeared to have clear cleavage planes with the surrounding structures, so the patient was proposed for an exploratory laparotomy. Prior to the surgery, an additional pelvic computed tomography (CT) was performed (10 months after the first one), which did not show progression of the disease. The histological examination result was compatible with a benign retroperitoneal schwannoma and not an ovarian tumor. CONCLUSIONS This report highlights that the diagnosis of retroperitoneal and pelvic masses can be challenging. In women, a primary ovarian tumor should be excluded on imaging and the diagnosis of a benign tumor, such as schwannoma, must be confirmed by histopathology, either preoperatively or following tumor resection.