Long-term outcome in patients with prenatally diagnosed cystic lung disease: special reference to ventilation and perfusion scan in the affected lung

Background/Purpose

The natural history of cystic lung disease (CLD) such as congenital cystic adenomatoid malformation (CCAM) and pulmonary sequestration has been altered by the advent of prenatal diagnosis. Although recent advances including fetal therapy have gradually improved outcome, the long-term course and the function of the residual lung have not been well clarified.

Methods

Twenty-two patients with CLD who had been prenatally diagnosed and treated between 1990 and 2004 were reviewed. The clinical outcome and growth measurements were established, and, where possible, all infants underwent ventilation and perfusion lung scan.

Results

Mediastinal shift was present in 14 fetuses. Fetal hydrops was present in 5 fetuses. Antenatal intervention was performed for hydrops in 2 fetuses (cyst-amniotic shunt and aspiration). Twenty-one infants underwent appropriate excisional surgery. Final diagnosis included CCAM (n = 12) and pulmonary sequestration (n = 7). No late death was observed. Common complications were failure to thrive (n = 5), frequent respiratory tract infection (n = 4), and asthmatic attack (n = 4). A significant decrease in lung ventilation and perfusion on the affected side was observed in patients with hydrops, lobectomy, and CCAM.

Conclusion

Long-term follow-up including respiratory care and growth assessment should be performed in prenatally diagnosed patients with CLD, especially those who present with hydrops.     

Outcome predictors for infants with cystic lung disease

Background/purpose

This study aimed at identifying characteristic features indicating congenital cystic adenomatoid malformation of the lung (CCAM) and evaluating the outcome predictors to identify prenatally subgroups of fetuses with significantly different probabilities of mortality or severe respiratory difficulty.

Methods

Twenty-eight neonates who had undergone antenatal evaluation for cystic lung disease (CLD) were reviewed retrospectively. The patients were divided into 3 groups according to the severity of their clinical course; mild (n = 7), moderate (n = 13), and severe (n = 8). Ultrasonographic findings in the fetus and their pulmonary lesion were evaluated. The normal lung to thorax transverse area ratio (L/T) was measured by ultrasonography.

Results

High echogenicity of the lesion throughout pregnancy and polyhydramnios were frequently seen in CCAM. All of the patients with other CLD showed isoechogenicity at the end of pregnancy. All patients in the severe group had both polyhydramnios and fetal hydrops. L/T was increased in mild and moderate groups, whereas no patient in the severe group had an increase in L/T at the final measurement. Each value of final L/T in the severe group was less than 0.25.

Conclusions

The subgroup of fetuses with an increased probability of mortality or severe respiratory difficulty could be predicted from the combination of polyhydramnios, fetal hydrops, and a final L/T value of less than 0.25.     

Characteristics of congenital cystic adenomatoid malformations associated with nonimmune hydrops and outcome

Background/Purpose

In fetuses with congenital cystic adenomatoid malformations of the lung (CCAMs), hydrops fetalis and large masses are associated with poor outcomes. This study attempts to (1) determine sonographic features (in addition to large size) that correlate with hydrops and (2) characterize the features that correlate with outcome among hydropic fetuses.

Method

Charts and sonograms of fetuses with large, unilateral CCAMs were retrospectively reviewed. Mass features evaluated included laterality, macrocystic/microcystic, cystic/solid predominance, degree of mediastinal shift, retrocardiac component, diaphragm eversion, polyhydramnios, and mass-thorax ratio (MTR). Features of hydrops included degree of ascites, scalp and integumentary edema, pleural/pericardial effusion, and placentomegaly.

Results

Thirty-six fetuses with large CCAMs were studied: 27 with and 9 without hydrops. Three sonographic features were significantly associated with hydrops: MTR of at least 0.56, cystic predominance of mass, and eversion of hemidiaphragm. Of 27 fetuses with hydrops, 10 (37%) demonstrated all 3 features compared with none in those without hydrops (P = .04). All 9 nonhydropic fetuses were expectantly managed, and 100% survived. In the hydropic group, none of the expectantly managed fetuses survived, and 10 (43%) of the 21 fetuses who underwent fetal intervention survived.

Conclusion

Three features of large CCAMs were significantly associated with hydrops: MTR, cystic predominance, and diaphragm eversion. Identification of these features will allow clinicians to accurately predict which fetuses may warrant closer follow-up and possible treatment.     

Prenatal steroids for microcystic congenital cystic adenomatoid malformations

Objective

The purpose of this study is to evaluate the effect of prenatal steroid treatment in fetuses with sonographically diagnosed congenital cystic adenomatoid malformations (CCAMs).

Methods

This was an institutional review board-approved retrospective review of 372 patients referred to the University of California, San Francisco (UCSF), for fetal CCAM. Inclusion criteria were (1) a predominately microcystic CCAM lesion sonographically diagnosed at our institution, (2) maternal administration of a single course of prenatal corticosteroids (betamethasone), and (3) no fetal surgery. CCAM volume-to-head ratio (CVR), presence of hydrops, mediastinal shift, and diaphragm eversion were assessed before and after administration of betamethasone. The primary end points were survival to birth and neonatal discharge.

Results

Sixteen patients with predominantly microcystic CCAMs were treated with prenatal steroids. Three were excluded because of lack of follow-up information. All remaining fetuses (13/13) survived to delivery and 11/13 (84.6%) survived to neonatal discharge. At the time of steroid administration, all patients had CVR greater than 1.6, and 9 (69.2%) also had nonimmune hydrops fetalis. After a course of steroids, CVR decreased in 8 (61.5%) of the 13 patients, and hydrops resolved in 7 (77.8%) of the 9 patients with hydrops. The 2 patients whose hydrops did not resolve with steroid treatment did not survive to discharge.

Conclusion

In high-risk fetal patients with predominantly microcystic CCAM lesions, betamethasone is an effective treatment. This series is a pilot study for a prospective randomized trial comparing treatment of CCAM with betamethasone to placebo.     

Large fetal congenital cystic adenomatoid malformations: growth trends and patient survival

Purpose

The prognosis for fetuses with large congenital cystic adenomatoid malformations (CCAMs) remains uncertain. This study examined the natural history of large fetal CCAMs managed expectantly at a major referral center.

Methods

A 5-year retrospective review was conducted on fetuses diagnosed with a thoracic lesion (n = 59). Large CCAMs were identified on prenatal imaging and followed longitudinally. Perinatal outcomes were assessed.

Results

Twelve (20.3%) fetuses had large CCAMs in the absence of other congenital anomalies. Peak CCAM size occurred at 25.3 ± 3.6 weeks' gestation. Serial magnetic resonance volumetry demonstrated a trend toward decreasing CCAM mass volume relative to thoracic cavity volume over time. Overall, 6 patients, including 3 with signs of early hydrops, showed a marked regression of their lesions relative to estimated fetal weight. Five fetuses required an emergent intervention postnatally, including extracorporeal membrane oxygenation support (n = 1), cyst aspiration (n = 1), and lung resection (n = 5). Overall survival was 75%, with severe hydrops before 30 weeks seen in all 3 deaths.

Conclusion

Large fetal CCAMs tend to peak in size at 25 weeks' gestation and are characterized by in utero diminution relative to overall fetal growth. The prognosis for most fetuses with large CCAMs remains quite favorable under careful perinatal management.     

Neonatal outcomes associated with intestinal abnormalities diagnosed by fetal ultrasound

Purpose

Intestinal abnormalities are sometimes seen during antenatal testing; however, the postnatal importance of these findings has not been well established. We evaluated whether abnormal intestinal appearance on fetal ultrasound (US) was ultimately related to neonatal outcome.

Methods

Fetal US examinations from 2003 to 2006 were evaluated. Hyperechogenic bowel was defined as having the echogenicity comparable to bone, and dilated bowel was identified based on the sonographer's assessment. Persistence or resolution of US findings on subsequent US examinations and eventual outcomes were assessed. Cases were categorized as hyperechogenic or dilated and then subgrouped based on whether the US finding resolved.

Results

Sixty-eight fetuses had either hyperechogenic (n = 48) or dilated bowel (n = 20) on antenatal US. In 56 cases, complete data were available for analysis. Of 44 liveborn infants, 11 (25.0%) had an abdominal abnormality, and 33 (75.0%) were normal at birth. Compared to those with dilated bowel, fetuses with hyperechogenic bowel had a higher rate of prenatal demise (20.8% vs 10%) but a lower rate of abnormality at birth (10.3% vs 53.3%). Hyperechogenic bowel resolved on subsequent US more frequently than dilated bowel (65.5% vs 20.0%). In both groups, all fetuses with sonographic resolution were normal at birth. Of 9 fetuses that had persistently hyperechogenic bowel, 3 (33.3%) were born with an abnormality, and all were found to have meconium peritonitis or meconium ileus. In the 12 cases where dilated bowel did not resolve, 8 (66.7%) were eventually born with an abnormality, most commonly intestinal atresia.

Conclusions

Hyperechogenic and dilated bowel are associated with a significant rate of fetal demise. Hyperechogenicity is more common than dilation and is more likely to be transient. Dilated bowel is more often associated with neonatal abnormality than hyperechogenic bowel. Persistence of fetal US findings predicts a higher likelihood of abnormality in the neonate.     

Clinicopathologic assessment of prenatally diagnosed lung diseases

Purpose

To investigate the clinical features and pathologic diagnosis of prenatally diagnosed lung diseases.

Materials and Methods

The medical records of 28 fetuses with prenatally diagnosed lung diseases were reviewed with regard to perinatal courses, ultrasonographic measurement of the lesion volume ratio, and the histopathology of lung tissue.

Results

Of the 23 fetuses with a prenatal diagnosis of congenital cystic adenomatoid malformation (CCAM), 4 required an emergency lobectomy (1 prenatally and 3 postnatally), whereas the other 14 showed uneventful courses after birth. The pathologic diagnosis of the resected lungs included CCAM (n = 4), lobar emphysema (n = 2), intralobar sequestration (n = 2), and bronchial atresia (n = 1). The peak value of the lesion volume ratio was significantly higher in the CCAM cases that required urgent surgery than in the non-CCAM cases (2.29 ± 0.46 vs 1.20 ± 0.21, P < .001). The ratio decreased after the 25th to the 30th week to less than 1.0 in the 5 non-CCAM cases, but remained higher than 2.0 in the 4 CCAM cases. Prenatally diagnosed extralobar pulmonary sequestration caused massive pleural effusion requiring a fetal intervention in 4 of the 5 fetuses.

Conclusions

The prenatally diagnosed lung lesions include various kinds of pulmonary diseases. Regardless of the diseases, sequential ultrasonographic assessment may predict perinatal risks.     

Prenatal diagnosis and outcome of fetal lung masses

Aim

The purpose of this study is to evaluate the accuracy of prenatal diagnostic features, particularly congenital cystic adenomatoid malformation volume ratio (CVR), in predicting outcomes for fetuses with lung masses.

Methods

The records and imaging features of all fetuses referred to the Texas Children's Fetal Center with a fetal lung mass between July 2001 and May 2010 were reviewed retrospectively. Data collected included gestational age (GA) at diagnosis, fetal magnetic resonance imaging findings, CVR, mass size, nature of fetal treatment, surgical findings, pathology, and outcome. Data were analyzed for predicting development of hydrops or the need for fetal therapy using receiver operating characteristic curves.

Results

Of 82 fetuses (41 male) evaluated for a lung mass, 53 (65%) were left-sided (1 bilateral), and the mean (SD) GA at diagnosis was 21.5 (4.3) weeks. Seventy-three fetuses underwent fetal magnetic resonance imaging at a mean (SD) GA of 26.1 (4.6) weeks. Thirteen fetuses (16%) had fetal treatment. Four fetuses with hydrops underwent open fetal surgical resection, and 3 survived. Six fetuses with large lung masses and persistent mediastinal compression near term underwent ex-utero intrapartum therapy-to-resection procedures, and 3 fetuses with hydrops underwent serial thoracentesis. Congenital cystic adenomatoid malformation volume ratio correlated strongly with the development of hydrops and the need for fetal therapy with an area under the receiver operating characteristic curve of 0.96 (P < .0001) and 0.88 (P < .0001), respectively. Of 18 fetuses with a CVR greater than 2.0 compared with 2 (3%) of 60 with a CVR of 2.0 or less, 10 (56%) required fetal intervention (P < .0001).

Conclusion

Congenital cystic adenomatoid malformation volume ratio correlates strongly with the development of fetal hydrops and the need for fetal intervention. A threshold value of 2.0 yields the most powerful statistical results.     

Congenital diaphragmatic hernia: prognostic indices in the fetal endoluminal tracheal occlusion era

Introduction

Management of congenital diaphragmatic hernia (CDH) in the UK now includes the possibility of fetal endoluminal tracheal occlusion (FETO) for poor prognosis fetuses. The objective of this study was to investigate the value of variables previously thought prognostic in the FETO era.

Methods

A retrospective single-centre study was performed of all infants with CDH born between January 1994 and December 2007. Fetal endoluminal tracheal occlusion was available and had been used with parental consent for fetuses with lung-to-head ratio (LHR) of 1.0 or less and a liver-up position from 2002. Univariate analysis was used to predict survival (to leave hospital) using both prenatal (eg, polyhydramnios) and perinatal variables [eg, best oxygenation index on day 1, or BOI (d1)] and their dependence tested in a logistic regression model. Data were quoted as medians (range). P < .05 was regarded as significant.

Results

Eighty-six infants with CDH (1994-2002, n = 35 and 2002-2007, n = 51 “FETO era”) were studied. Successful FETO intervention was performed in 31 infants.Univariate analysis showed liver position, birth weight, LHR, and BOI (d1) were significant prognostic predictors (all P < .05); however, only BOI (d1) retained significance using logistic regression analysis (odds ratio, 21; 95% confidence interval, 6-74; P < .001). Best oxygenation index on day 1 was then used as a surrogate marker for outcome to test the relationship with LHR (available since 2002) and showed a significant inverse correlation (r_s = −0.5; P < .001). There was no difference in median BOI (d1) between the FETO group and all those treated expectantly (40 [34-1046] vs 59 (23-581); P = .3].

Conclusion

Best oxygenation index on day 1 is the best early postnatal predictor of survival. The more recently evaluated prenatal index, LHR, has an observable relationship with BOI (d1) when it is used as a surrogate marker of outcome.     

Vesicoamniotic shunt for complete urinary tract obstruction is partially effective

Purpose

The long-term outcome for children after antenatal intervention for obstructive uropathies is disappointing. We reported that renal dysplastic changes are well established 3 weeks after obstruction in a fetal lamb model. We used this model to explore renal development and bladder function after fetal intervention.

Methods

We created an obstructive uropathy in fetal lambs at 60 days gestation by ligating the urethra and urachus. A vesicostomy (female) or urethrostomy (male) were performed 21 days later. The fetuses were killed at term (145 days) and bladder volume and compliance were measured. The urinary tract was processed for histologic examination.

Results

Twenty two fetuses were shunted. Nine were miscarried or were still-born. Thirteen survived, and 11 had a successful shunt with a small bladder (8 ± 5 mL) compared with controls (71 ± 19 mL) (P < .05). Shunted bladders had poor compliance. Histologically, they had thickened submucosal connective tissue with hypertrophied muscle. Histology of the renal tissue demonstrated relatively well-preserved renal architecture with reduced nephron mass (oligonephronia) in 2 lambs and multicystic dysplastic change in 3. Six (55%) had normal nephrogenesis.

Conclusions

In our model, shunt operations after obstructive uropathy fail to preserve bladder function. Shunting ameliorated the development of cystic dysplasia, but half of the lambs had oligonephronia or multicystic dysplastic kidney. These might develop renal failure later in life.     

Intrapulmonary perfluorooctyl bromide instillation in fetal rabbits

Background

Instilling perfluorooctyl bromide (PFOB) into the fetal lung may lead to alveolar distension.

Objective

The aim of the study was to evaluate the safety of PFOB instillation into fetal lungs and to determine the radiographic distribution and tissue concentration of PFOB in New Zealand white rabbits.

Methods

Sibling fetuses of pregnant (day 27) New Zealand white rabbits were randomized to intratracheal instillation of 1 mL PFOB with tracheal ligation, instillation without ligation, and unmanipulated controls. The maternal animals were killed directly after instillation, at 3 or 6 hours (n = 10 each). For each study cohort, we determined fetal lung/body weight (FLBW) ratios, the radiographic distribution of PFOB, as well as pulmonary PFOB and water content by tissue distillation. PFOB concentrations in maternal and fetal tissues were assessed by gas chromatography.

Results

The relative amount of fetal lung PFOB recovered by fractional distillation was highest in ligated (25%) and lower in unligated lungs (9%). Extrapulmonary PFOB was found in the fetal brain (2.0 ± 0.7 ppm), but not in any other fetal or maternal tissues. Mean FLBW ratios were highest in ligated fetuses, followed by unligated fetuses and controls. PFOB partially displaced fetal lung water. PFOB was visible in the lungs of all treated fetuses. Fetal survival between manipulated and unmanipulated fetuses did not differ.

Conclusions

After prenatal intrapulmonary instillation, some PFOB remains in the lung, even if the trachea is not ligated, and may exert distending pressure on the alveoli.     

Outcome of antenatally diagnosed sacrococcygeal teratomas: single-center experience (1993-2004)

Aims

Sacrococcygeal teratomas (SCTs) are the commonest neonatal tumors with an incidence of approximately 1:30,000. There are few large single-center series and even fewer describing both their antenatal and postnatal course. We report the outcome of all fetuses investigated at a tertiary fetal medicine center with this diagnosis.

Method

Demographic details were obtained from a prospectively maintained database. Patient records were examined for additional data including antenatal and postnatal interventions. Data were described as median (range).

Results

Forty-one SCTs were diagnosed antenatally during the period 1993 to 2004. Twelve were excluded from subsequent analysis (single antenatal visit or attending for second opinion [n = 6] and termination of pregnancy [n = 6]). Twelve underwent fetal intervention (laser vessel ablation [n = 4], alcohol sclerosis [n = 3], cyst drainage [n = 2], amniodrainage [n = 2], vesicoamniotic shunt [n = 1]) for fetal hydrops and polyhydramnios to aid in delivery and to prevent obstructive uropathy developing in the fetus. Of these, 3 died in utero and 9 survived to be born (median gestational age, 33 weeks [27-37 weeks]). A further 3 died in the neonatal period. There are 6 long-term survivors (50%) from this group. Seventeen infants, without intervention, were born at median gestational age 38 weeks (26-40 weeks). One infant with severe cardiac anomalies died on the day of birth. All surviving infants had definitive excisional surgery at a median of 2 days (1-16 days). Current median follow-up of survivors is 39 months (8-86 months). There have been no recurrences. One child has mild constipation, and 3 are awaiting cosmetic revision of their scars.

Conclusions

The overall survival of antenatally diagnosed SCT is approximately 77%, with the development of hydrops and others requiring in utero intervention carrying a poor prognosis. Otherwise, the outcome after surgical excision is excellent.     

The bispectral index, a useful adjunct for the timely diagnosis of brain death in the comatose trauma patient

Background

The bispectral index (BIS) is a processed electroencephalographic value (awake = 100, isoelectric = 0). The relationship of BIS and brain death (BD) is assessed.

Methods

BIS was evaluated in GCS 3 head-injured patients with BD (no brain function including apnea) or near BD (no apnea or negative ancillary test [cerebral perfusion and electroencephalogram]).

Results

In 27 patients, there were 37 BD evaluations (apnea assessment or ancillary test). BD was confirmed in 62% (n = 23). However, 38% (n = 14) showed near BD. BD BIS is 3 ± 5 and near BD BIS is 36 ± 31 (P = .002). In the 23 BD patients, BIS was <20 for 7 hours ± 6 hours before a BD evaluation was performed. Of 14 near BD evaluations, 9 (64%) had BIS ≥20. BIS <20 for predicting BD had a sensitivity of 100% (23/23), a positive predictive value of 84% (23/28), and a negative predictive value of 100% (9/9).

Conclusions

Distinguishing brain death and near brain death in severely comatose trauma patients is complex. By indicating the likelihood of brain death, BIS is an adjunct for efficient evaluation.     

Closing gastroschisis: diagnosis, management, and outcomes

Purpose

Gastroschisis (GS) is defined as a full-thickness abdominal wall defect (usually right-sided) with intestinal prolapse and occasionally other viscera. The defect itself may close around the viscera causing exit or entry level intestinal atresia and ischaemia or midgut infarction, previously described as closed GS. We now report the largest series of infants born with various stages of closing GS describing features, management, and outcome.

Methods

The study used a single-centre retrospective review of infants with GS and evidence of defect closure at birth.

Results

Nine infants (6 girls) with a median of 35 (range, 32-36) weeks of gestation fulfilled criteria for closing GS from a series of 146 (6%) infants born from August 1994 to December 2007. Delivery had been expedited in 6 based on increasing intraabdominal bowel dilatation and suspicion of closing GS on serial antenatal ultrasound. At delivery, 5 had compromised but viable bowel and required intestinal surgery.Three fetuses, all with midgut necrosis, had antenatal scans typical of GS with no additional features.After a variety of surgical procedures, 7 patients are now fully enterally fed, one is parenteral nutrition-dependent. One died of end-stage liver failure secondary to short bowel syndrome. The length of follow-up was 6 (range, 0.5-11) years.

Conclusions

Of infants with GS, 6% present with closing abdominal ring. Close antenatal monitoring may prevent severe bowel loss in some cases. After multiple surgical interventions, most have a favorable outcome.     

Survival of severe congenital diaphragmatic hernia has morbid consequences

Background/Purpose

Fetal tracheal occlusion (TO) was developed in an attempt to enhance prenatal lung growth and improve survival in fetuses with severe congenital diaphragmatic hernia (CDH). We conducted a randomized, controlled clinical trial in 24 fetuses with severe left CDH (liver herniated into the thorax and low lung-to-head ratio) to compare survival after endoscopic fetal TO vs standard perinatal care (control) and prospectively followed up the 16 survivors (9 control, 7 TO) to compare neurodevelopmental, respiratory, surgical, growth, and nutritional outcomes.

Methods

At 1 and 2 years old, subjects underwent evaluation consisting of medical and neurological history and physical, developmental testing, nutritional assessment, oxygen saturation and pulmonary function testing, chest radiograph, and echocardiogram. Growth and developmental measures were corrected for prematurity. Data were analyzed by Mann-Whitney rank sum test, Fisher's Exact test, and logistic and linear regression.

Results

Infants with TO were significantly more premature at birth (control vs TO, 37.4 ± 1.0 vs 31.1 ± 1.7 weeks; P < .01). Growth failure (z score for weight <2 SDs below mean) was severe in both groups at 1 year of age (control vs TO, 56% vs 86%; P = .31). There was considerable catch-up growth by age 2 years (growth failure: control vs TO, 22% vs 33%; P = .19). There were no differences in other growth parameters. There were also no differences in neurodevelopmental outcome at 1 and 2 years. Supplemental oxygen at hospital discharge was a significant predictor of worse neurodevelopmental outcome at 1 and 2 years old (P = .05 and P = .02, respectively). Hearing loss requiring amplification has been diagnosed in 44% of the group (control vs TO, 44% vs 43%; P = 1.0).

Conclusions

In this group of infants with severe CDH, there were no differences in outcome at 2 years old despite significant prematurity in the TO group. Oxygen supplementation at hospital discharge identified the most vulnerable group with respect to neurodevelopmental outcome, but all infants had significant growth failure, and hearing impairment is a substantial problem in this population. Severe CDH carries significant risk of chronic morbidity.     

Lentiviral vector-mediated, in vivo gene transfer to the tracheobronchial tree in fetal rabbits

Background/Purpose

Fetal gene replacement is a novel, potential therapy for antenatally diagnosed monogenic disorders. The purpose of this study was to evaluate in vivo techniques of lentiviral (LV) vector-mediated gene transfer to the tracheobronchial tree in a rabbit model of fetal gene therapy.

Methods

Via triple plasmid transfection, vesicular stomatitis virus-G-pseudotyped LV vector containing green fluorescent protein (GFP) reporter gene under the control of a cytomegalovirus promoter was constructed.In vivo gene transfer of 5 × 10⁶ LV particles to fetuses of time-mated NZW rabbits (term = 31 days) was attempted using 2 techniques: (1) direct amniotic injection (gestation = 24-26 days) and (2) direct tracheal injection (gestation = 26 days). Injected fetuses and saline-injected littermate controls were delivered and killed on gestational day 30. Fetal and maternal tissues were analyzed.

Results

Both in vivo techniques produced gene transfer to fetal tissues (trachea, lung, liver, intestine), including those of some controls. In one prep, GFP DNA was identified in maternal lung.

Conclusions

Lentiviral vector-mediated GFP gene transfer to fetal rabbit tracheobronchial epithelium occurs within 4 days of transfection by both amniotic injection or direct fetal tracheal injection. This in vivo model confirms bioavailability of vector through amniotic fluid with some cross-infection of adjacent fetuses. Vector access to fetal tissues appears to be by both luminal and hematogenous routes. Transplacental gene transfer from fetus to mother may occur in this model.     

Tumor volume to fetal weight ratio as an early prognostic classification for fetal sacrococcygeal teratoma

Purpose

This study was designed to develop a prognostic factor for fetuses with sacrococcygeal teratoma (SCT) that may be useful to predict outcome and guide counseling early in pregnancy. We hypothesize that, in fetuses with SCT, the ratio of tumor size to estimated fetal weight in the second trimester predicts outcome.

Methods

We retrospectively reviewed charts of all patients evaluated at our Fetal Center for SCT between 2004 and 2009. Estimated fetal weight and tumor volume were calculated based on prenatal ultrasound or fetal magnetic resonance imaging. Patients were stratified based on tumor volume to fetal weight ratio (TFR), and their outcomes were analyzed by Fisher's Exact test.

Results

Tumor volume to fetal weight ratio before 24 weeks' gestation was predictive of outcome. Those with a TFR less than or equal to 0.12 (n = 5) had a significantly better outcome than patients with a TFR greater than 0.12 (n = 5, P < .05). All patients with poor outcomes had a TFR greater than 0.12 by 24 weeks' gestation. A TFR greater than 0.12 predicted poor outcome with 100% sensitivity and 83% specificity. All 4 patients who developed hydrops had a TFR greater than 0.12.

Conclusion

In our series of fetuses with SCT, TFR before 24 weeks' gestation correlates with outcome. This novel, prenatal diagnostic tool may be useful in prenatal counseling and for early identification of high-risk fetuses.