Fetus in fetu: two case reports and literature review.
BACKGROUND
Fetus in fetu is a rare congenital anomaly and is defined as a monozygotic twin incorporated into the abdomen of its sibling during development. Fetus in fetu is often overlooked in the differential diagnosis of an abdominal mass. Unlike teratomas, fetus in fetu is a benign disorder.


METHODS
We describe the clinical characteristics of two patients, a thirty-months old boy who was found to have abdominal distension and a neonate who was diagnosed antenatally with abdominal mass. Computed tomography scan revealed the mass in which the contents favor a fetus in fetu rather than a teratoma. Surgical removal revealed that the anencephalic fetus have limb buds situated relative to a palpable vertebral column, supporting the diagnosis of fetus in fetu. In the present report, presentation, diagnosis, pathology, management, and recent literature are also reviewed.


CONCLUSIONS
Fetus in fetu is a rare entity that typically presents in infancy and early childhood. It should be differentiated from a teratoma because of the teratoma's malignant potential. Preoperative diagnosis is based on radiologic findings. The treatment of fetus in fetu is operative to relieve obstruction, prevent further compression and possible complications. Complete excision allows confirmation of the diagnosis and lowers the risk of recurrence.
Division of Oncology, Department of Pediatric Surgery, West China Hospital of Sichuan University, 37# Guo-Xue-Xiang, Chengdu 610041, China. jijiyuanyuan@163.com.
Yi
Y
Ji
Siyuan
S
Chen
Lin
L
Zhong
Xiaoping
X
Jiang
Shuguang
S
Jin
Feiteng
F
Kong
Qi
Q
Wang
Caihong
C
Li
Bo
B
Xiang
D000005:Abdomen / Q000000981:diagnostic imaging; D002114:Calcinosis / Q000209:etiology; D002675:Child, Preschool; D005333:Fetus / Q000002:abnormalities*; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D011860:Radiography, Abdominal; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography