Fetal intra-abdominal Tumors: Assessment of spectrum, accuracy of prenatal diagnosis, perinatal outcome and therapy at a tertiary referral center

Objective: To describe the varieties and ultrasound characteristics of prenatally diagnosed fetal abdominal tumors and to scrutinize the accuracy of prenatal diagnosis as well as the postnatal outcome and therapy of affected pregnancies. Study design: Retrospective study of 354 fetuses found to have abdominal tumors on prenatal sonogram, identified from 1993 to 2009 at a tertiary referral center for prenatal medicine. The cohort was classified into subgroups according to the sonographic appearance of the fetal tumor and the affected anatomic structure (urinary, gastrointestinal and genital tracts and other locations). Sensitivity, specificity, positive predictive value and false-positive rate of ultrasonography in identifying the system of origin were calculated. Relationships between relevant outcome domains and the different subgroups were assessed using the chi-square test and Fisher's exact test. Results: Our cohort comprised 222 urinary tract lesions, 37 genital tract lesions, 80 gastrointestinal lesions and 15 tumors of other origins. The mean gestational age at diagnosis was 26 + 0 wks. The prenatally established diagnosis was exactly concordant with postnatal findings in 88.9%. Sensitivity, specificity, positive predictive value and false-positive rate of ultrasonography in identifying the system of origin (urinary, gastrointestinal, genital tracts and other locations) were 98.3%, 97.6%, 92.6% and 2.4%, respectively. The favorable postnatal outcome rate was highest among fetuses with genital tract lesions (95%) and lowest among those with tumors of the urinary tract (62%, p = < 0.001). Twenty per cent of tumors regressed spontaneously, mostly gastrointestinal tumors (36%, p = < 0.001). In 75/354 cases (21%) the parents opted to terminate the pregnancy: intra-uterine fetal demise and neonatal death were each noted in 4%. Prenatal therapy was performed in 24 of 354 cases (7%) and postnatal surgery in 64 cases (18%). Conclusion: The majority of fetal abdominal anomalies were accurately diagnosed and the vast majority of affected fetuses had a favorable outcome, some tumors even resolved with advancing pregnancy. Pre- and post-natal invasive surgical interventions were mandatory in only a small number of cases.