We present a 42 years old female patient with lower abdominal pain. Transabdominal ultrasonography (US) examination detected acute appendicitis and also incidentally showed an anechoic homogenous cystic mass with a thin wall, which located anterior part of the urine bladder. There was no connection seen between urinary bladder and adjacent structures. Computed tomography (CT) revealed a cystic mass at the dome of the urinary bladder and magnetic resonance imaging (MRI) findings were similar to sonographic and CT findings.