A Giant Leiomyoma with Massive Cystic Hydropic Degeneration Mimicking an Aggressive Neoplasm: A Challenging Case with a Literature Review.

BACKGROUND Leiomyomas are the most frequent benign tumors of the uterus. They often exhibit degenerative changes (hyaline, myxoid, hemorrhagic, hydropic, and cystic), which lead to varying and sometimes challenging clinical, radiological, and histopathological features. We present this case to highlight the importance of recognizing these variants and their differential diagnosis since they resemble forms of uterine sarcomas with a potential for misdiagnosis. CASE REPORT A 32-year-old single woman presented with large pelviabdominal masses mimicking, clinically and radiologically, an aggressive uterine or ovarian tumor. The masses collectively measured 33×24×15 cm, and a definite intraoperative diagnosis could not be made. Resection showed a giant leiomyoma with massive cystic hydropic degeneration. The patient underwent myomectomies with transposition of the ovaries into the lateral abdominal wall. Although the surgery was complicated by a massive hemorrhage with an approximate blood loss of 6 liters requiring blood transfusion and bilateral internal iliac artery ligation, the patient was discharged home on the fourth day after surgery, with an uneventful 16-month follow-up. CONCLUSIONS Few leiomyomas showing this marked degree of hydropic degeneration have been reported in the literature. The differential diagnosis includes uncommon variants of leiomyomas (eg, intravenous leiomyomatosis), as well as uterine sarcomas (eg, low-grade endometrial stromal sarcoma) and ovarian carcinomas. Therefore, appropriate evaluation of the clinicopathological features is vital to ensure appropriate management and not to erroneously diagnose a benign leiomyoma as a more aggressive type of tumor.