A case report of red degeneration of a uterine fibroid mimicking ovarian malignancy in the postpartum period: a diagnostic challenge.

Introduction and importance: Red degeneration of uterine fibroids, though uncommon postpartum, can mimic ovarian malignancies both radiologically and biochemically. This case is unique because the patient had no previously identified fibroid during pregnancy, yet presented in the early postpartum period with an unusually large mass, tumor marker elevation, and imaging features virtually indistinguishable from ovarian dysgerminoma. Case presentation: We report the case of a 37-year-old multiparous woman (G3P3) who presented on the fourth postpartum day with progressive abdominal distension and discomfort. Detailed clinical examination and imaging pointed toward an adnexal mass, likely right ovarian dysgerminoma. Tumor markers, including CA-125 (cancer antigen 125) and β-hCG (beta-human chorionic gonadotropin), were elevated. A staging laparotomy was planned based on the presumptive diagnosis of ovarian malignancy, which revealed a large fundal uterine fibroid undergoing red degeneration. The patient underwent a total abdominal hysterectomy. Clinical discussion: The presence of an adnexal or pelvic mass in the postpartum period presents diagnostic complexity. Red degeneration is a hemorrhagic infarction of a uterine fibroid. The definite diagnosis is often confirmed by laparotomy and histologic confirmation. Tumor markers may be falsely elevated in postpartum women or in association with benign gynecological conditions. Red degeneration should be part of the differential diagnosis when a postpartum woman presents with an abdominopelvic mass, especially if she has a known fibroid. Conclusion: This case underscores the importance of integrating clinical, biochemical, and radiologic data in the diagnosis of uterine fibroids - while remaining open to alternate benign diagnoses at the same time - to avoid overtreatment or delayed appropriate management.