Fetus in fetu: A rare case of intra-abdominal mass

External fetus in fetu presenting in the second trimester: A case report and literature review

Fetus in fetu (FIF) is a rare congenital anomaly that originates from various sites of the host twin's body. The clinical manifestations of FIF are diverse and the location and size of FIF indicate the degree of threat, which may directly affect the prognosis. A 33-year-old woman presented at the hospital with an abdominal mass in her fetus. Prenatal ultrasound observed that mass included soft tissue, bone-like structures, and fluid. Immature cartilage, nerve tissue, muscle tissue, and glands in the parasitic fetus without signs of neoplastic lesions were reported by histological examination. CNV (copy number variation) and WES (whole exome sequencing) did not detect any abnormal mutations. FIF can continue to grow with gestational age or host infant growth. So complete resection is essential for improving the outcome of the host twin. It is also important that long-term follow-up is recommended to monitor any residual or recurrent cysts or malignancies.

Retroperitoneal fetus in fetu presenting in a male infant: A case report and literature review

Fetus in fetu (FIF) is a rare congenital disease caused by the abnormal development of monochorionic diamniotic twins that appears as a cystic mass containing fetus-like structures mainly in the retroperitoneum of infants. The clinical manifestations of fetus in fetu vary, but they mostly present at infancy, hence, it should be differentiated from a teratoma. Here, we report a case of an infant with fetus in fetu in the retroperitoneum. Enhanced computed tomography scans and three-dimensional images showed a huge mixed-density mass on the left side of the abdominopelvic cavity with patchy distribution of fat, intact bones, and soft tissue. The child underwent fetus in fetu resection under general anaesthesia. Histopathology confirmed that the mass contained skin, muscle, intestinal mucosa, bones and cartilage, nerves, muscles, fat, and bone marrow tissue.

A cohort of five cases with asymmetric conjoined twining and literature review

PURPOSE

Asymmetric conjoined twining (ACT) is a form of conjoined twining which is a rare malformation of monochorionic monoamniotic twin pregnancy. Most publications were single case reports. We reported a cohort of five cases with ACT from a single tertiary medical center and reviewed the case reports of ACT over the last decade to enrich the clinical research of this disease and summarized the clinical features of the disease.

METHODS

We reviewed five cases of ACT admitted in Tianjin Children's Hospital from 17 March, 2008, through 7 March 2017. The cohort was analysed from general information, imaging manifestations, separation surgery, histopathological findings, outcome and follow-up. We searched the English literatures on case reports of ACT over the past decade from the PubMed database and presented details about the clinical characteristics, treatment, and prognosis of all cases.

RESULTS

There were four males and one female in our cohort. Among the five cases, two parasites were located in epigastrium, two in rachis, and one in retroperitoneum (fetus in fetu, FIF). All of the parasites were separated successfully by operation in five cases and were confirmed to be ACT by histopathology reports. Four patients made an uneventful recovery except for one case of wound infection. All of them were doing well in follow-up. In the literature review, we found 41 cases of exoparasitic heteropagus twining (EHT) and 63 cases of FIF.

CONCLUSIONS

ACT is very rare and usually diagnosed by prenatal ultrasonography (US). Computed tomography (CT) and magnetic resonance imaging (MRI) examinations are essential imaging examinations before separation surgery to delineate the anatomical relationship between the autosite and the parasite. In general, the separation surgery of ACT is less complicated and the prognosis is better compared with the symmetric conjoined twining (SCT).

Is Fetus in Fetu a Reason for Vascular Anatomy Changes in the Host?

Fetus in fetu (FIF) is a rare congenital anomaly. Anomalies of inferior vena cava (IVC) in the host are rare and not reported in the literature. In this case report, the surgical management and the findings of a rare vascular anomaly of IVC in a 10-month-old male child with FIF are discussed. This case highlights the importance of antenatal ultrasonogram in the detection of FIF and to diligently look for structural anomalies of IVC in the host in such cases.

Fetus in fetu: two case reports from North African country

Background

Fetus in fetu is a rare congenital anomaly. The exact etiology is unclear; one of the mostly accepted theories is the occurrence of an embryological insult occurring in a diamniotic monochorionic twin leading to asymmetrical division of the blastocyst mass. Commonly, they present in the infancy with clinical picture related to their mass effect. About 80% of cases are in the abdomen retroperitoneally.

Case presentation

We present two cases of this rare condition. The first case was for a 10-year-old girl that presented with anemia and abdominal mass, while the second case was for a 4-month-old boy that was diagnosed antenatally by ultrasound. Both cases had vertebrae, recognizable fetal organs, and skin coverage. Both had a distinct sac. The second case had a vascular connection with the host arising from the superior mesenteric artery. Both cases were intra-abdominal and showed normal levels of alpha-fetoprotein. Histopathological examination revealed elements from the three germ layers without any evidence of immature cells ruling out teratoma as a differential diagnosis.

Conclusions

Owing to its rarity, fetus in fetu requires a high degree of suspicion and meticulous surgical techniques to avoid either injury of the adjacent vital structures or bleeding from the main blood supply connection to the host. It should be differentiated from mature teratoma.

Fetal teratomas - A retrospective observational single-center study

OBJECTIVE

Evaluation of course and outcome of pregnancies with prenatally diagnosed fetal teratomas of various locations in a single center between 2002 and 2019.

METHODS

Retrospective observational single-center study including prenatally suspected or diagnosed fetal teratomas. Focus was put on ultrasound findings during pregnancy. Complications, need for intervention and outcomes were compared according to tumor location.

RESULTS

79 cases of fetal teratomas were seen at our center between 2002 and 2019. Most frequent tumor locations were the sacrococcygeal region (59.5%), neck (20.2%) and oropharynx (7.6%). Complications mainly included polyhydramnios and cardiac compromise. Need for intervention during pregnancy was significantly higher in pericardial teratomas. Preterm birth before 37 and early preterm birth before 32 weeks occurred in 72.7% and 29.1%, respectively. Major causes of perinatal death were tumor bleeding in sacrococcygeal teratomas (SCTs) and respiratory failure in cervical and oropharyngeal teratomas.

CONCLUSION

There is a high need for intervention in pregnancies complicated by fetal teratomas. Pericardiocentesis in pericardial teratomas is often inevitable to reduce the risk of intrauterine demise. Amniotic fluid drainage in associated severe polyhydramnios helps to reduce the risk of preterm birth, a major cause of additional morbidity and mortality. MRI in supplement to prenatal ultrasound is useful in fetal teratomas of the neck and oropharynx in order to plan delivery.

Preoperative diagnosis of a "humanoid" fetus in fetu using multimode ultrasound: a case report

Background

Fetus in fetu (FIF) is a rare congenital anomaly. The preoperative diagnosis of FIF and differentiating it from teratoma and other abdominal tumors can be challenging for radiologists. Clarification of the blood supply and the relationship with the surrounding vessels is especially helpful for successful surgery; however, multimode ultrasound (US) performed for FIF has rarely been explored. Here, we first report a “humanoid” FIF case diagnosed by multimode US examinations, with the use of contrast-enhanced ultrasound (CEUS) for clarifying the blood supply features.

Case presentation

A 25-day-old preterm male infant was referred to our hospital for surgery. The US and computed tomography (CT) examinations led to a diagnosis of teratoma at the local hospital. The laboratory workup at our hospital revealed an elevation of total bilirubin, direct bilirubin, indirect bilirubin, alpha-fetoprotein, and neuron-specific enolase levels. A precise diagnosis and differentiation from teratoma, hepatoblastoma, neuroblastoma and other abdominal tumors were needed. In addition, the blood supply and the relationship with the surrounding vessels needed clarification prior to surgery. Multimode US examinations were performed and the features of a “humanoid” FIF as well as the blood supply for the abdominal lesion of the infant were suggested by grayscale US, color Doppler flow imaging (CDFI), and CEUS. Furthermore, CDFI and CEUS revealed an aorta-like structure and umbilical cord-like blood vessels in the “humanoid” FIF, and the CEUS helped with marking the surface of the infant’s abdominal wall. To the best of our knowledge, this is the first case report of CEUS in FIF, and the blood supply was clearly demonstrated in the FIF. The intraoperative findings confirmed our multimode US findings and revealed a “humanoid” FIF. The infant quickly recovered after the operation and had no positive findings at the 2-year follow-up visit.

Conclusions

Multimode US was helpful in diagnosing the rare FIF without radiation exposure. Specifically, CEUS clearly demonstrated the limb branch vessel-like structures, the abdominal aorta-like structure and the blood supply, which was useful for the FIF diagnosis and for avoiding damage to important vessels during the operation.