Sonographic and Clinical Characteristics of Uterine Sarcoma Initially Misdiagnosed as Uterine Fibroid in Women in the Late Reproductive Age

OBJECTIVES: Uterine sarcoma is a rare malignant tumor, which is usually diagnosed in postmenopausal women. These sarcomas are occasionally misdiagnosed as uterine fibroids, thereby leading to delayed diagnosis in the advanced stages. We analyzed the sonographic and clinical characteristics of unexpected uterine sarcomas detected after surgery in women in the late reproductive age. METHODS: The medical records of 61 patients preoperatively diagnosed with uterine leiomyomas through sonography but confirmed as uterine sarcomas after surgery from January 2005 to December 2018 at Asan Medical Center were retrospectively analyzed. We evaluated the clinical symptoms, sonographic findings, and Doppler indexes, and investigated whether there were any significant characteristics that could clearly differentiate uterine sarcoma from fibroids. RESULTS: The most common clinical finding was increased mass size (15 patients, 24.6%), while 9 patients (14.8%) showed no symptoms. Ultrasonography showed that the maximum diameter of most fibroids was > 5 cm (49 patients, 80.3%), and the average diameter was 75.6 ± 36.3 mm. All the patients showed heterogeneous echogenicity in sonographic imaging. Secondary degeneration of the myomas was reported in 36 patients (59%), and approximately 90% (32/36, 88.9%) showed cystic changes. Of the 40 patients who underwent the evaluation of vascularity, 35 showed increased vascularity of the mass. CONCLUSIONS: In this study, sarcomas misdiagnosed as leiomyomas were usually > 5 cm, and ultrasonography showed heterogeneous echogenicity and irregular cystic degeneration. No definite clinical symptoms were helpful; a thorough evaluation is necessary to rule out uterine sarcomas in women having uterine mass with these characteristics.