Mucinous ovarian cystadenomas are rare epithelial benign tumors that can reach significant sizes. They are often asymptomatic and are discovered incidentally during an ultrasound examination. We present two clinical cases of mucinous ovarian cystadenomas with abdominal distention. Complicated variants can mimic an acute surgical abdomen and often require the involvement of a multidisciplinary team in operative treatment. Timely diagnosis and treatment are of utmost importance to prevent complications and malignancy.