Primary pelvic retroperitoneal smooth muscle tumor with cystic degeneration: a case report and review of the literature.

BACKGROUND: Primary retroperitoneal tumors are sporadic and most often malignant. Primary pelvic retroperitoneal smooth muscle tumors are a very rare benign disease that occurs most often in female patients, especially in perimenopausal women. Its occurrence is often hormone-related. Most of them are easily overlooked and misdiagnosed because of their early nonspecific clinical manifestations. The preoperative diagnosis and treatment of this condition present significant challenges. routine postoperative pathology and immunohistochemistry are required to confirm the diagnosis. CASE PRESENTATION: The patient was a 34-year-old woman of childbearing age with no history of uterine fibroids, a history of one cesarean section, and no clinical symptoms. Imaging revealed a cystic solid mass of approximately 6.2 × 5.3 cm in the right adnexal region. Tumor markers suggested that the alpha-fetoprotein level was above the normal range, and all other indicators were within the normal range. On exploration, a solid mass of approximately 5.0 × 6.0 cm with an abundant blood supply and a smooth surface was observed in the pelvic retroperitoneal. The mass was completely excised. Anatomical pathology: pelvic retroperitoneal smooth muscle tumor with cystic degeneration. CONCLUSION: Primary pelvic retroperitoneal smooth muscle tumors, although rare, should always be included in the diagnosis when a solid pelvic mass is discovered in a female patient.