Retroperitoneal leiomyoma: a case report.

Background: Retroperitoneal leiomyomata are rare neoplasms. These masses can be asymptomatic or can cause pelvic discomfort, urinary frequency, abdominal fullness or back pain.

Case: A 28-year-old, nulliparous female presented with worsening dysmenorrhea and bulk symptoms from fibroids. MRI revealed an exophytic anterior lower uterine segment fibroid with internal degeneration. During surgery the fibroid was discovered to be retroperitoneal in location, contrary to preoperative imaging findings. Pathology confirmed a benign leiomyoma.

Conclusion: The treatment for these masses is complete excision. The retroperitoneal location of this fibroid was not evident on preoperative ultrasound and MRI. Imaging can be used only as a guide for operative planning and does not always represent the anatomy accurately. Surgical excision is required, and only at surgery will the exact anatomical location of the fibroid be ascertained.