Enteric duplication cysts are rare congenital anomalies, but their antenatal diagnosis is becoming more common because of advances in ultrasonography. With the latest state-of-the-art technology, HDlive facilitates a more realistic anatomical visualization of different fetal organ structures, making diagnosis more precise. We present a case of antenatal HDlive imaging of an enteric duplication cyst. A 26-year-old pregnant Japanese woman was referred to our ultrasound clinic because of a fetal intra-abdominal cyst at 27 weeks of gestation. Two-dimensional (2D) ultrasound revealed a sonolucent, ellipsoid structure in the subhepatic area. Magnetic resonance imaging yielded the same findings. However, irregular internal echoes appeared at 33 weeks of gestation. There was no vascularity on color Doppler. HDlive clearly depicted a more realistic image of the circular mass, which was thick walled, with a large amount of debris inside, and showed no communication with adjacent structures. Careful monitoring was conducted for these unusual findings. A day after delivery, an emergency operation was performed because the infant had sudden signs and symptoms of obstruction. Intra-operative findings were ileus and a necrotic ileal duplication cyst confirmed by histopathologic studies. Complications of enteric duplication cyst can arise at any time of life, and so thorough monitoring may be recommended. The findings of irregular internal echoes and a large amount of debris inside the cyst are relatively characteristic features of a complicated cyst. HDlive gives us additional information on the actual appearance of a complicated cyst that may be difficult to obtain using conventional 2D sonography alone. HDlive can be very useful in the antenatal surveillance of enteric duplication cysts.