Retroperitoneal parasitic fetus: A case report

Area of Science:

• Medical Science
• Congenital Anomalies
• Surgical Case Reports

Background:

• Fetus-in-fetu (FIF) is an exceptionally rare congenital anomaly characterized by a vertebral axis connecting a developed fetus to a malformed twin.
• FIF masses are often discovered incidentally during prenatal examinations or present in neonates with abdominal distension.

Observation:

• A male infant presented with a retroperitoneal mass detected at 25 gestational weeks, initially suspected as a teratoma.
• Postnatal examination revealed a distinctive limb with five toes within the abdominal mass.
• Magnetic resonance imaging (MRI) and ultrasonography were crucial in visualizing the anomalous structure.

Findings:

• The retroperitoneal mass, measuring approximately 10 cm in diameter, was surgically excised at 26 days of age.
• Postoperative pathological examination confirmed the diagnosis of fetus-in-fetu.
• Imaging and histological analysis were essential for definitive diagnosis.

Implications:

• This case underscores the importance of advanced imaging techniques in diagnosing rare congenital anomalies like FIF.
• Early surgical intervention is critical for successful management and improved outcomes in infants with FIF.
• Reporting such rare cases contributes valuable data for understanding the pathogenesis and clinical presentation of fetus-in-fetu.