Congenital absence of ribs is a rare condition that can occur either as an isolated anomaly or as part of a syndromic presentation. While rib agenesis has been documented postnatally in several case reports, there is a notable lack of antenatal detection cases in the literature. We present a unique case involving a primigravida patient who was referred for a routine anomaly scan at 20 weeks of gestation. During the ultrasound examination, significant findings were observed: the fetus exhibited unilateral agenesis of the left fifth to eighth ribs, along with dysmorphic features in the adjacent ribs on the same side. Additionally, a right-sided lumbar supernumerary rib and various vertebral segmentation anomalies were identified, which further complicated the clinical picture.
The three-dimensional (3D) transabdominal ultrasound proved to be an invaluable tool in clearly visualizing the bony defects and structural abnormalities associated with this condition. The enhanced imaging capabilities allowed for a more detailed assessment of the rib cage and surrounding anatomical structures, enabling a comprehensive understanding of the extent of the rib agenesis and its implications for the developing fetus. This antenatal detection is particularly significant, as it underscores the potential for early diagnosis of rib anomalies, which can be crucial for planning further management and intervention if necessary.
In conclusion, our case of unilateral rib agenesis detected antenatally through 3D ultrasound represents a notable addition to the medical literature, highlighting the importance of advanced imaging techniques in identifying rare congenital anomalies. This case serves to enhance awareness of the complexities associated with rib agenesis and the role of ultrasonography in antenatal evaluations.
