Caudal regression versus sirenomelia: sonographic clues

Area of Science:

• Medical imaging
• Pediatric pathology
• Prenatal diagnosis

Background:

• Caudal regression syndrome and sirenomelia are rare congenital anomalies.
• Distinguishing between these conditions prenatally is crucial for management and understanding etiology.
• Previous studies suggest potential differences, but clear antenatal sonographic markers are needed.

Purpose of the Study:

• To review antenatal sonographic findings in cases diagnosed with caudal regression or sirenomelia.
• To identify distinct sonographic features that differentiate caudal regression syndrome from sirenomelia.
• To correlate these findings with maternal history, particularly diabetes.

Main Methods:

• Retrospective review of seven cases with antenatal sonography and pathologic/autopsy diagnosis.
• Analysis of sonographic findings including amniotic fluid volume, urinary system status, limb fusion, and sacral agenesis.
• Correlation of findings with maternal medical history.

Main Results:

• Caudal regression cases showed normal/increased amniotic fluid, normal/mildly dilated urinary systems, nonfused extremities, and sacral agenesis.
• Sirenomelia cases exhibited marked oligohydramnios, suspected renal agenesis, and sacral agenesis.
• Maternal diabetes was present in all caudal regression cases but none with sirenomelia.

Conclusions:

• Antenatal sonography reveals distinct patterns for caudal regression syndrome and sirenomelia.
• Maternal diabetes is a significant risk factor for caudal regression syndrome.
• These findings support caudal regression syndrome as a separate entity from sirenomelia.