Case Report: The Medical and Surgical Management of an Infant With Extreme Prematurity and Fetus-In-Fetu

Abstract

Fetus-in-fetu (FIF) is a rare congenital anomaly where a parasitic twin is within the body of a host twin. FIF is reported to occur in 1:500,000 live births. Herein, we report the first case of the medical and surgical treatment of a FIF patient who was born with extreme prematurity at 25-weeks gestation. With the multi-disciplinary coordination of neonatology, surgery, and interventional radiology, the patient was able to achieve a window of medical stability 4 weeks after birth. A decision was made at that time to proceed with an intra-abdominal and perineal resection of the FIF. The FIF was successfully resected and the patient was able to recover from the operation, with eventual discharge from the NICU. In conclusion, extreme prematurity and FIF may be amenable to surgical resection and a multi-disciplinary approach is crucial to achieve the desired outcome.

Keywords: Fetus-in-fetu; congenital - diagnosis; etiology; fetal; prematurity; surgery.

Figure 1

Oblique sagittal T2 weighted fetal MR images demonstrate the large FIF spanning the host twin perineum, with markedly edematous legs of the parasitic twin within the abdominal cavity of the host.

Figure 2

Fetus-in-fetu prior to operative resection.

Figure 3

Parasitic twin with both the abdominal and extracorporeal sacral component dissected and exposed.

Figure 4

Pathologic features of resected FIF with gross examination showed a malformed fetus with rudimentary upper (black arrows) and lower (white asterisks) extremities. Brain covered by dura (red arrow) was present; cranial bones were absent. A possible rudimentary umbilical cord (yellow arrow) was seen connecting the abdomen of the FIF to a sac-like membranous structure (white triangle). Left inset shows two feet connected to rudimentary legs opposite to the site of asterisks. Note both feet contains six toes. Right inset shows rudimentary, presumed left hand which is deviated and contained four digits. The other hand (no inset) had two digits.