MRI reveals fetus in fetu in the mediastinum

Fetus in fetu is an extremely rare condition in which a fetiform calcified mass is contained within the newborn or infant, often in the retroperitoneal cavity. We report a case of a fetus in fetu in the posterior mediastinum of a newborn. The prospective diagnosis was made by fetal US and MRI and confirmed by postnatal plain radiograph, CT and MRI.     

Fetus in fetu: a case report

A fetus in fetu is defined as a condition where a parasitic twin is found included within the body of its partner [8]. This is a report of a fetus in fetu treated successfully in a 4-mounth-old boy that fulfilled all the criteria of the disease. A brief review of the literature is also included.     

Fetus in fetu

Fetus in fetu is a rare condition in which a monozygotic, monoamniotic, dichorionic twin is included within the body of its sibling [19]. In 1956, Lord presented the first systematic review of the subject, comprising 11 case reports including 1 of her own. She found that many of the earlier reports dealt with teratomas and not true fetus in fetu. In 1958, Willis defined fetus in fetu as a benign mass with a vertebral column, as identified by radiography or at dissection, with other bones and organs arranged around the axis. This is to be differentiated from a true teratoma, which shows no axial arrangements and has definite malignant potential [26]. This paper presents a case occurring in a newborn male and a review of the literature since Lord's initial review. Offprint requests to: S. Sutherland     

Fetus in fetu of the face

A fetus in fetu of the face is described. The preoperative diagnosis was teratoma. The resected specimen weighed 200 g and had two parts. The lateral part was enclosed within a thick capsule and consisted of a well-formed lower limb, a spinal column comprised of 3 vertebrae, and a small piece of intestine in the form of a saccule. The medial part contained fibrofatty tissue only. The developmental etiology of this phenomenon and its relationship to teratoma are discussed.     

Fetus in fetu: report of three cases and review of the literature

Fetus in fetu, or parasitic twin, is an uncommon condition in which a malformed fetus grows within the body of its twin. It is almost always detected as an abdominal mass in infancy: 41 cases have been reported since 1806 and 89% of the patients were less than 1 year old. We have reviewed the literature and report three new cases from our own experience. All patients available were considered from the point of view of their clinical findings, preoperative diagnosis, surgical and anatomic-histological aspects. We also suggest the possibility of including those cases otherwise defined as teratomas with a high grade of structural complexity (limbs, well formed organs, or parts of systems) in this pathological group even if they do not show a real vertebral column according to Willis' definition.     

Twin fetus in fetu

Fetus in fetu is a rare cause of intra-abdominal mass. The presence of vertebral and skeletal axis differentiates it from a teratoma.¹ We report an unusual case of two well developed fetuses in the retroperitoneal area of a neonate delivered at term.     

Fetus in fetu

A 1-year-old boy presented with a mass in the right upper abdomen. The radiological findings and gross features of the resected specimen indicated it to be a fetus in fetu rather than a teratoma.     

Prenatal diagnostic clue for fetus in fetu

The purpose of this paper is to define a prenatal diagnostic clue for fetus in fetu (FIF) based on the characteristic findings of four FIF cases studied by the authors. A retrospective analyses of prenatal ultrasonography (US), postnatal US, computed tomography (CT) scans and operative findings were carried out on each of the four FIF cases collected from a multi-center. Prenatal US findings for each of the four cases showed a fluid-filled sac with a solid portion “floating” within it. In addition, bony structures were found in the solid portion. In each of the four cases, the postpartum imaging studies were consistent with the prenatal US findings. Operative findings revealed a solid mass within a fluid-filled sac surrounded by a transparent membrane. The solid mass was connected to the membrane by a stalk. Histopathologically, the cells making up the sac were of the same type as those of the amnion, while the solid mass had the general characteristics of FIF. In conclusion, FIF can be suspected when prenatal US shows a solid mass with bony structures within a fluid-filled sac in a newborn.     

Fetus in fetu: report of an additional, well-developed case

 An 8-month-old boy presenting with a fast-growing abdominal mass was operated upon to remove the tumor, which was confirmed to be a well-formed fetus in fetu. The authors describe the clinical, radiologic, and surgical findings and review the literature. Accepted: 11 May 2000     

Aborted thoracopagus

A case of aborted thoracopagus is reported. The parasite having all the features of a normal baby except head and thorax, was successfully separated from autosite.     

Double fetus in fetu

Fetus in fetu (FIF) is an extremely rare cause of infantile abdominal mass where a rudimentary, malformed monozygotic-diamniotic twin grows inside the other twin. We describe a male infant with double or twin fetuses in fetu. The diagnosis was made on a computerized tomography (CT) scan of the abdomen and confirmed on surgery. Surgical excision was done and the baby did well post operatively.     

Intraperitoneal testicular fetus in fetu

A 5-month-old boy presented with a right flank abdominal mass. Plain film of the abdomen showed a vertebral column within the mass. Surgery confirmed the diagnosis of fetus in fetu developed within an ectopic intraperitoneal right testicle. Fetus in fetu differs from teratoma by the presence of axial skeleton and organogenesis. When intratumoral axial skeleton is present, plain films are sufficient for the diagnosis.     

Oropharyngeal true teratoma

Oropharyngeal teratoma in newborn is very rare. Here we report a case of oropharyngeal true teratoma where a 17-day-old female baby presented with a protruding mass from oropharynx with episodic respiratory distress and feeding difficulty complicated by aspiration pneumonia, and treated successfully with coordinated team approach.     

Double fetus in fetu: Diagnostic imaging

Fetus in fetu is a rare pathological condition, presenting as a congenital tumor. It consists of a malformed parasitic twin that is found within the body of its sibling. Less than 70 cases have been reported and in most of them a definite diagnosis was only made during surgery. We present a case with two fetuses in the retroperitoneum and describe the criteria to be kept in mind for a correct preoperative diagnosis, using the current imaging modalities.     

Abdominal mass: "fetus in fetu"

A female newborn presented a mass in the left upper abdominal quadrant. It was removed by surgery and contained two independent fetuses. Dissection and radiological study of the fetuses showed an axial skeleton and long bones. It corresponds to the generally recognized diagnostic criteria of fetus in fetu.     

Fetus in Fetu: A Case with Complete Umbilical Cord and Fetal Sac

The authors present a retroperitoneal fetus in fetu in a 3-month-old girl. A 15-cm cystic mass with a monstrous fetuslike structure surrounded by a complete sac containing serous fluid was removed from the left retroperitoneal space. The draining vessel of the cystic mass was connected to the right renal vein of the host. The included fetus weighed 380 g. It had a well-developed umbilical cord, four extremities, head, buttock, and vertebral bodies with a meningomyelocele. The thoracic cavity of the included fetus had only a saclike foregut structure, but the abdominal cavity revealed a full length of intestine with a Meckel diverticulum, bilateral ovaries, urinary bladder, and cloaca with external opening. The cephalic end was composed of well-developed tooth germs, tongue and buccopharynx, mandible, maxilla, sphenoid bone, and salivary glands. Chromosomal study showed 46,XX with a normal G banding pattern. We report this case as an example of fetus in fetu with a complete umbilical cord and fetal membrane.     

Intrapericardial teratoma diagnosed prenatally in a twin fetus

Prenatal diagnosis at 32 weeks' gestation of an anteromediastinal tumor in a twin fetus allowed immediate neonatal intensive management after delivery at 34 weeks' gestation. At 48 h of age the patient underwent a median sternotomy; complete resection of the tumor was possible. Histologically, it was a mature teratoma. At age 1 year both twins are well. Accepted: 26 May 1998