Fetus-in-fetu (FIF) is a rare entity resulting from abnormal embryogenesis in diamniotic monochorionic twins, being first described by Johann Friedrich Meckel (1800s). This occurs when a vertebrate fetus is enclosed in a normally growing fetus. Clinical manifestations vary. Detection is most often in infancy, the oldest reported age being 47. We report the case of a 4-day-old girl who was referred postnatally following a prenatal fetal scan which had revealed the presence of a multi-loculated retroperitoneal mass lesion with calcifications within. A provisional radiological diagnosis of FIF was made. Elective laparotomy revealed a well encapsulated retroperitoneal mass containing among other structures a skull vault and rudimentary limb buds. Recovery was uneventful. Here we discuss the difference between FIF and teratomas, risks of non-operative therapy and the role of serology in surveillance and detection of malignant change.
Fetus in fetu is an extremely rare condition wherein a malformed fetus is found in the abdomen of its twin. This entity is differentiated from teratoma by its embryological origin, its unusual location in the retroperitoneal space, and the presence of vertebral organization with limb buds and well-developed organ systems. The literature cites less than 100 cases worldwide of twin fetus in fetu.
A two-and-a-half-month-old Asian Indian baby boy had two malformed fetuses in his abdomen. The pre-operative diagnosis was made by performing an ultrasound and a 64-slice computer tomography scan of the baby's abdomen. Two fetoid-like masses were successfully excised from the retroperitoneal area of his abdomen. A macroscopic examination, an X-ray of the specimen after operation, and the histological features observed were suggestive of twin fetus in fetu.
Fetus in fetu is an extremely rare condition. Before any operation is carried out on a patient, imaging studies should first be conducted to differentiate this condition from teratoma. Surgical excision is a curative procedure, and a macroscopic examination of the sac should be done after twin or multiple fetus in fetu are excised.
Fetus in fetu is a rare abnormality secondary to the abnormal embryogenesis in a diamniotic, monochorionic pregnancy. It is a rare pathological condition and fewer than 100 cases have been reported in the literature.
A 2 month old girl with an abdominal mass since birth, was referred to the Cancer Institute with a suspected diagnosis of a Wilms' tumor. Conventional radiograph of the abdomen revealed a mass containing numerous calcifications. CT scan showed a heterogeneous retroperitoneal mass containing well-defined calcified structures. The decision was made to recommend surgical exploration and the mass was successfully excised. Physical examination of the mass with review of literature confirmed the diagnosis of fetus in fetu.
Although it is a rare condition imaging may play an important role in the correct prospective diagnosis of fetus in fetu. Surgical excision is the recommended treatment.
Fetus in fetu is a rare congenital anomaly in which malformed fetus grows within the body of its twin. It is almost always detected as an abdominal mass in infancy. It is a parasitic twin of a diamniotic, monozygotic twin. It should be differentiated from teratoma which has no axial arrangement and has got definite malignant potential. Herein, we present a case of a two-month old female infant and review the literature. Although fetus in fetu is a rare condition, correct diagnosis using imaging can be made before surgery. It should be considered as a differential diagnosis for lump abdomen especially in infants. Complete excision is curative.
Fetus in Fetu; Teratoma; Twin
Fetus-in-fetu (FIF) is a rare anomaly in which a vertebrate fetus is enclosed within the body of its twin in diamniotic monochorionic pregnancy. To the best of our knowledge, fewer than 100 cases have been reported in literature. Although a wide variety of presentations have been described in clinical reports, the characteristic features on MRI which distinguish FIF from teratoma have not been well delineated. Here we present a case of fetus-in-fetu in which characteristic MDCT and MR findings were used to diagnose FIF preoperatively and successfully differentiate it from teratoma. Although both CT and MRI can be used for definitive preoperative diagnosis of FIF, MRI is an ideal imaging modality due to inherent high tissue contrast and spatial resolution. Furthermore, MRI obviates the need for iodine contrast and eliminates the risk of ionizing radiation. We emphasize that MRI is an ideal valuable diagnostic tool for definite preoperative diagnosis of FIF and surgical planning.
fetus-in-fetu; teratoma; axial skeleton; diamniotic monochorionic twins; parasitic twin; multidetector computed tomography; magnetic resonance imaging
Triploid pregnancies have an increased risk of early preeclampsia. Twin pregnancies consisting of one healthy fetus and one complete or partial molar, with or without a triploid fetus, are rare and management is complex.
A 33-year-old Caucasian woman presented with a dichorionic diamniotic twin pregnancy. One fetus showed early growth restriction resulting in fetal death at 20 weeks. The placenta was enlarged with some cysts. Chorionic villus biopsy confirmed triploidy. At 21 weeks, the patient developed preeclampsia with a blood pressure of 154/98 mmHg and proteinuria (24 hour protein excretion of 2.5 g/L), for which she was hospitalized. Without pharmacological interventions, the blood pressure normalized and proteinuria disappeared. At 35 weeks, she again developed preeclampsia. A cesarean section was performed at 38 weeks and a healthy child was born.
Survival of the healthy fetus is possible in a twin pregnancy with a triploid fetus complicated by early preeclampsia. The pregnancy should not be terminated if the triploid twin has died and as long as conservative management is safe.
A fetus-in-fetu (FIF) is an uncommon developmental abnormality characterized by a reasonably well-formed but aborted fetus that is seen in the form of an encapsulated, pedunculated vertebrate tumor in the patient's abdomen. We report an interesting case of a double FIF in a 20-year-old man, who presented with acute abdominal pain and a lump. CT scan of the abdomen revealed two ill-formed fetuses-in-fetu, which were seen as a 15-cm complex, encapsulated mass in the lower retroperitoneum; there was also free fluid in the abdomen. The diagnosis of a ruptured twin FIF was made. Complete surgical excision of the lesion was performed and the diagnosis was confirmed histopathologically. To the best of our knowledge, the CT scan findings of a ruptured double FIF in an adult have not been previously documented.
Fetus-in-fetu; Computed Tomography
Fetus-in-fetu (FIF) is a rare congenital condition in which a fetiform mass is detected in the host abdomen and also in other sites such as the intracranium, thorax, head, and neck. This condition has been rarely reported in the literature. Herein, we report the case of a fetus presenting with abdominal cystic mass and ascites and prenatally diagnosed as meconium pseudocyst. Explorative laparotomy revealed an irregular fetiform mass in the retroperitoneum within a fluid-filled cyst. The mass contained intestinal tract, liver, pancreas, and finger. Fetal abdominal cystic mass has been identified in a broad spectrum of diseases. However, as in our case, FIF is often overlooked during differential diagnosis. FIF should also be differentiated from other conditions associated with fetal abdominal masses.
Fetus in fetu; Meconium peritonitis; Misdiagnosis
Campylobacter fetus can be divided into the subspecies C. fetus subsp. fetus and C. fetus subsp. venerealis. C. fetus subsp. fetus causes sporadic infections in humans and abortion in cattle and sheep and has been isolated from a variety of sites in different hosts. C. fetus subsp. venerealis is host restricted, being isolated mainly from the genital tracts of cattle, and is the causative agent of bovine genital campylobacteriosis. Despite differences in niche preference, microbiological subspecies differentiation has proven difficult. Different typing methods divided C. fetus isolates into different subgroups, depending on the methods used. The relative value of these methods can be assessed by the evolutionary relationship of isolates belonging to the genus; therefore, we developed a multilocus sequence typing (MLST) scheme for C. fetus. This scheme was applied to 140 C. fetus isolates previously typed by amplified fragment length polymorphism (AFLP) analysis. A total of 14 different sequence types (STs) were identified, and these exhibited low levels of inter-ST genetic diversity, with only 22 variable sites in 3,312 nucleotides. These MLST data indicate that C. fetus is genetically homogeneous compared to the homogeneity of other Campylobacter species. The two C. fetus subspecies were extremely closely related genetically, but ST-4 was associated only with C. fetus subsp. venerealis, which represents a “bovine” clone. The C. fetus subsp. fetus isolates studied were more diverse in terms of their STs, and the STs correlated with epidemiological relationships. Congruence was observed among C. fetus subspecies, sap type, and ST; therefore, MLST confirms that mammalian C. fetus is genetically stable, probably as result of the introduction of a single ancestral clone into a mammalian niche.
Fetus in fetu is a rare condition that has been defined as the presence of one of the twins in the body of the other. It is most frequently located in retroperitoneal area; however, it has been reported in other locations as well. This report presents two cases of “fetus in fetu” cases: one located in the retroperitoneal area and the other in the sacrococcygeal area.
Fetus in fetu; newborn; teratoma
Introduction. A rare case of histologically proven placental mesenchymal dysplasia (PMD) with fetal omphalocele in a 22-year-old patient is reported. Material and Methods. Antenatal ultrasound of this patient showed hydropic placenta with a live fetus of 17 weeks period of gestation associated with omphalocele. Cordocentesis detected the diploid karyotype of the fetus. Patient, when prognosticated, choose to terminate the pregnancy in view of high incidence of fetal and placental anomalies. Subsequent histopathological examination of placenta established the diagnosis to be placental mesenchymal dysplasia. Conclusion. On clinical and ultrasonic grounds, suspicion of P.M.D. arises when hydropic placenta with a live fetus presents in second trimester of pregnancy. Cordocentesis can detect the diploid karyotype of the fetus in such cases. As this condition is prognostically better than triploid partial mole, continuation of pregnancy can sometimes be considered after through antenatal screening and patient counseling. However, a definite diagnosis of P.M.D. is made only on placental histology by absence of trophoblast hyperplasia and trophoblastic inclusions.
Spontaneous monochorionic triamniotic pregnancy is rare and is at increased risk for pregnancy complications. The presence of an anomalous fetus further complicates the management.
We present a case of monochorionic triamniotic triplet pregnancy diagnosed at 15 weeks of gestation with one fetus having developed a multicystic lung lesion, suggestive of congenital cystic adenomatoid malformation (CCAM). At 24 weeks, the largest cyst measured 10 mm in diameter. We managed the pregnancy conservatively and delivered three live male fetuses with birth weights 1560 g, 1580 g and 1590 g at 35 weeks of gestation. Two newborns were admitted to the neonatal intensive care unit with respiratory distress, the third one died due to sepsis 7 days postpartum. One of the newborns was discharged healthy at 24 days postpartum. The newborn with CCAM developed a pneumothorax on the right side, recovered after treatment, and was discharged after one month. Computerized tomography (CT) of the infant at 3 months demonstrated two cystic lesions in the middle lobe of the right lung measuring 25 mm and 15 mm. A repeat CT of the infant at 6 months showed a 30 mm solitary cystic mass.
Monochorionic triamniotic triplet pregnancy with a co-triplet fetus discordant for CCAM, present rarely and can be managed conservatively. These findings may help in decision making and counselling of parents.
Rupture of a renal artery aneurysm (RAA) during pregnancy is a rare event, with a high mortality rate for both mother and fetus. Increased blood flow and intra-abdominal pressure, and vascular changes secondary to increased steroid production are postulated as contributory to the increased risk of rupture during pregnancy.
We present here a case report of total avulsion of solitary kidney secondary to rupture of RAA in a pregnant patient with congenital absence of the contralateral kidney. The main indication for nephrectomy was severely damaged kidney. Diagnosis was made during operation and both mother and fetus were saved. There are no previous reports of an intact renal artery aneurysm diagnosed either antepartum or postpartum.
The possibility of a ruptured RAA should be considered in pregnant women with evidence of retroperitoneal hemorrhage. This case was unusual because it occurred in a solitary kidney, during the third trimester of pregnancy.
“Fetus in fetu” (FIF) is defined as the abnormal monozygotic twin inside the body of its “host twin.” Intracranial FIFs are extremely rare.
A male premature newborn was admitted to the hospital due to a large intracranial tumor diagnosed in the 31st week of gestation. The child died before surgical treatment because of failure of the respiratory system due to fetal respiratory distress syndrome. During general autopsy, a large intracranial tumor with four relatively well-developed limbs was found. Microscopically, apart from relatively well-formed musculoskeletal structures of limbs that were covered with skin, there were haphazardly distributed different tissues or fragments of organs. However, various neuroectodermal derivatives were dominant.
We believe that intracranial FIFs, theoretically with poor prognosis, can be successfully curable in cases revealed prenatally, provided that optimal treatment is introduced and the achievement of proper pulmonary maturity of the host is accomplished prior to the operation of the tumor.
Intracranial; Fetus in fetu; Teratoma; Tumor
Accurate estimates of the ultrasound pressure and/or intensity incident on the developing fetus on a patient-specific basis could improve the diagnostic potential of medical ultrasound by allowing the clinician to increase the transmit power while still avoiding the potential for harmful bioeffects. Neglecting nonlinear effects, the pressure/intensity can be estimated if an accurate estimate of the attenuation along the propagation path (i.e., total attenuation) can be obtained. Herein, a method for determining the total attenuation from the backscattered power spectrum from the developing fetus is proposed. The boundaries between amnion and either the fetus’ skull or soft tissue are each modeled as planar impedance boundaries at an unknown orientation with respect to the sound beam. A mathematical analysis demonstrates that the normalized returned voltage spectrum from this model is independent of the planes orientation. Hence, the total attenuation can be estimated by comparing the location of the spectral peak in the reflection from the fetus to the location of the spectral peak in a reflection obtained from a rigid plane in a water bath. The independence of the attenuation estimate and plane orientation is then demonstrated experimentally using a Plexiglas plate, a rat’s skull, and a tissue-mimicking phantom.
Asymmetric and parasitic conjoined twins are rarer anomalies of monochorionic monoamniotic twins, consisting of an incomplete twin attached to the fully developed body of the co-twin.
A 30-year-old multigravid woman referred to maternal fetal unit due to polyhydramnios at 28th week of gestation. Sonographic examination revealed a single fetus and polyhydramnios with amniotic fluid index 30 cm. The fetus had normal apparent single head, spine, thorax, abdomen, two upper and two lower limbs, and two relatively well developed rudimentary parasitic lower limbs at sacral region. Lower limbs of the autosite were moving freelly but no movement was detected at the parasite. The parasite contained irregular lower limbs and left foot with three toes. Short and deformed long bones were also present in the parasitic limbs. A Cesarean section was performed at 38th week of gestation and a live female infant weighing 3600 g was delivered. The parasitic lower limbs were totally excised. Post-operative period was uneventful and the newborn was discharged as healthy. Post-natal follow-up was normal at nine-month-old.
Pygopagus tetrapus parasitic twin is a rare form of conjoined twins and in utero diagnosis with ultrasound assists in prenatal management and counselling with parents.
A 30-years-old Taiwanese female in her second pregnancy spontaneously conceived a monochorionic twin pregnancy. A routine ultrasound at 27 weeks of gestation revealed a selective intrauterine growth restriction (sIUGR) fetus and an appropriate gestational age (AGA) fetus. The AGA fetus was found to have a fetal intra-abdominal umbilical vein (FIUV) varix. Serial ultrasounds showed no changes in the FIUV varix. 2 weeks later, the pregnancy progressed to twin–twin transfusion syndrome (TTTS). Repeated amnioreductions were required at 29 and 30 weeks gestation. The babies were delivered by caesarean section at 31 weeks due to fetal distress in the sIUGR fetus. Both fetuses survived the neonatal period with problems of prematurity. The FIUV varix disappeared a few days after delivery.
intra-abdominal; multiple pregnancies; ultrasound; umbilical vein; varix
The availability of technological advances like ultrasonography (USG) and magnetic resonance imaging (MRI) has made the diagnosis of rudimentary horn pregnancy possible at an early gestation. However, in advanced pregnancy, such cases can sometimes pose a diagnostic dilemma and are recognized only when patient presents with abdominal pain and collapse and is taken for laparotomy. We report one such rare case of a nulliparous female who was carrying on well with her pregnancy till she developed symptoms of acute abdomen at 28 weeks of gestation. She underwent USG and MRI but it was only after laparotomy that a final diagnosis of a pregnancy in a rudimentary horn with placenta percreta perforating through the fundus could be made. There was a significant amount of hemoperitoneum; however, the horn was intact and the fetus could be salvaged. We excised the rudimentary horn with ipsilateral tube and ovary. Post operatively, both the mother and the baby were discharged in healthy condition.
Hemoperitoneum; placenta percreta; rudimentary horn pregnancy
Epidermoid cysts are benign developmental anomalies that are rarely observed in the oral cavity of neonate. If large in size, especially in the developing fetus or newborn infant, they can cause swallowing difficulty and occasionally respiratory difficulty. We report a case of epidermoid cyst in the oral cavity detected prenatal sonography. The sonographic finding was large cystic mass, measuring 30×25 mm. In this case, supplies and equipment for an emergency tracheostomy were made available prior to the delivery. However, the infant did not require intervention to secure the airway. The lesion was surgically excised, and histologic diagnosis was epidermoid cyst. After 6 months of follow up, the cyst had not recurred. This case illustrates the value of accurate prenatal diagnosis and planned perinatal management using a team approach.
Prenatal diagnosis; Epidermoid cyst; Oral cavity; Newborn
With development from immature fetus, to near-term fetus, to newborn, to adult, the cerebral vasculature undergoes a number of fundamental changes. Although, the near-term fetus is prepared for a transition from an intra- to extra- uterine existence, this is not necessarily the case with the premature fetus, which is more susceptible to cerebrovascular dysregulation. In the present study, we tested the hypothesis that the profound developmental and age-related differences in cerebral blood flow are associated with significant underlying changes in gene expression.
With the use of oligonucleotide microarray and pathway analysis, we elucidated significant changes in the transcriptome with development in sheep carotid arteries (CA).
We demonstrate a U-shaped relationship of gene expression during early life, compared to adult for major cerebrovascular network/pathways, e.g. gene expression in the premature fetus and newborn is considerably greater than that of the near-term fetus. Specifically, cell proliferation, growth, and assembly pathway genes were up-regulated during early life. In turn, compared to adult, mitogen activated protein kinase-extracellular regulated kinase, actin cytoskeleton, integrin signaling pathways were down-regulated during early life.
In cerebral vascular smooth muscle, the present studies demonstrated significant changes in important cellular and signaling pathways with maturational development.
Campylobacter fetus infection is a substantial problem in herds of domestic cattle worldwide and a rising threat in human disease. Application of comparative and functional genomics approaches will be essential to understand the molecular basis of this pathogen's interactions with various hosts. Here we report recent progress in genome analyses of C. fetus ssp. fetus and C. fetus ssp. venerealis, and the development of molecular tools to determine the genetic basis of niche‐specific adaptations. Campylobacter research has been strengthened by the rapid advancements in imaging technology occurring throughout microbiology. To move forward in understanding the mechanisms underlying C. fetus virulence, current efforts focus on developing suitable in vitro models to reflect host‐ and tissue‐specific aspects of infection.
Objective: To test the hypothesis that identical twins show no inter-twin differences in cardiovascular structure or physiology in fetal life unless there has been twin-twin transfusion syndrome.
Design: Unselected prospective case–control observational study of fetoplacental haemodynamics including echocardiography at a median of 24 (16.7 to 32.3) weeks, with postnatal confirmation of congenital heart disease or normality.
Setting: Fetal medicine unit.
Patients: 136 women with monochorionic diamniotic twin pregnancies, of which 47 fetal twin pairs (35%) had twin-twin transfusion syndrome.
Results: There were no haemodynamic differences between the bigger fetus (twin 1) and the smaller co-twin (twin 2) in uncomplicated monochorionic diamniotic pairs. In twin-twin transfusion syndrome, recipient fetuses had increased aortic and pulmonary velocities compared with their donor co-twins (mean (SD): 0.73 (0.23) m/s and 0.63 (0.14) m/s), respectively, v 0.53 (0.16) m/s and 0.48 (0.10) m/s in donor twins; p = 0.003 (aortic) and < 0.0001 (pulmonary)), and also in comparison with twin 1 and twin 2. The overall prevalence of congenital heart disease was increased above that in singletons (3.8% v 0.56%; 6.9% in twin-twin transfusion v 2.3% in uncomplicated monochorionic diamniotic twins), with inter-twin discordance for defects. The prevalence in recipient twins was 11.9% (p = 0.014 v uncomplicated control twins).
Conclusions: Fetuses with an identical genome but no circulatory imbalance have similar cardiovascular physiology but discordant phenotypic expression of congenital heart disease. The high prevalence of congenital heart disease in monochorionic diamniotic twins merits detailed fetal echocardiography.
monochorionic twins; twin-twin transfusion syndrome; congenital heart disease; fetal echocardiography
The development of empyema as a result of an intra-abdominal pathology is a rare condition.
PRESENTATION OF CASE
We present a 31-year-old woman at 28 weeks’ gestation who was referred to our hospital with diagnosis of pneumonia with pleural effusion. She presented with signs of septicemia and fetal distress. A thoracic-abdominal-pelvic CT-scan showed a right pleural effusion with a retroperitoneal collection in contact with the pleural space. Due to her critical condition, immediate surgical exploration and pregnancy interruption was decided. The fetus was delivered by cesarean with satisfactory vitality. After abdominal exploration, a retrocecal appendicular abscess was evidenced and appendectomy was performed. Subsequently, the right chest was accessed through a posterolateral thoracotomy. An empyema with lung abscess and purulent fluid accessing from the retroperitoneum at the posterior pleural space was found. Due to parenchymal compromise, a right inferior lobectomy was performed. The patient had an uneventful recovery and was discharged at postoperative day 10.
A septic condition in a pregnant patient with significant thoraco-abdominal infection requires an aggressive approach, with interruption of pregnancy and urgent exploration of the chest and abdomen.
When an empyema is developed in absence of lung disease or other intrathoracic cause, intra-abdominal origin should be considered.
Appendicitis; Empyema; Pregnant woman
Trafficking of cells between mother and fetus during the course of normal pregnancy is well documented. Similarly, cells are known to travel between twins that share either a placenta (i.e. monozygotic) or associated chorion (i.e. monochorionic). Transferred cells are thought to be channelled via the vessels of the placenta or vascular connections established via the chorion and the long-term presence of these cells (i.e. microchimerism) can have important consequences for immune system function and reparative capacity of the host. Whether cells can be transferred between twins with separate placentas and separate chorions (i.e. no vascular connections between placentas) has not been investigated nor have the biological consequences of such a transfer. In the present study, we tested the possibility of this type of cell transfer by injecting human cord blood-derived cells into a portion of the littermates of swine and probing for human cells in the blood and tissues of unmanipulated littermates. Human cells were detected in the blood of 78% of unmanipulated littermates. Human cells were also detected in various tissues of the unmanipulated littermates, including kidney (56%), spleen (33%), thymus (11%) and heart (22%). Human cells were maintained in the blood until the piglets were sacrificed (8 months after birth), suggesting the establishment of long-term microchimerism. Our findings show that the transfer of cells between fetuses with separate placentas and separate chorions is significant and thus such twins may be subject to the same consequences of microchimerism as monozygotic or monochorionic counterparts.
cord blood; maternofetal transfer; microchimerism; stem cells; tolerance
Two cases of fetus-in-fetu, on which we performed surgery in 2003 and 2006, are being reported. Both the cases presented with a lump in the abdomen. Radiology confirmed the diagnosis. The lumps were found in the retroperitoneum and successfully excised. Because of the rarity of the condition, these two cases are being reported with relevant salient features and are discussed in the light of available literature.
Abdominal lump; axial skeleton; fetus-in-fetu; retroperitoneal; teratoma