Biochemical analysis of cystic fluid in the diagnosis of fetal intra-abdominal masses.

OBJECTIVE: The aim of the study was to evaluate a biochemical analysis of fluid sampled in utero from fetal abdominal cystic masses. METHODS: A retrospective study of 42 intra-abdominal cystic masses [ovarian cysts (n = 22), cloaca (n = 8), urodigestive fistulae (n = 4), and urogenital sinuses (n = 8)] was carried out. The control group (n = 30) consisted of fetal urine. Seven biochemical markers were assayed: sodium, estradiol, ß(2) -microglobulin, total proteins and digestive enzymes, gamma-glutamyl transpeptidase, aminopeptidase M, and intestinal alkaline phosphatase isoenzyme. Outcome of pregnancies and final diagnosis of intra-abdominal mass were known in all cases. RESULTS: Biochemical patterns allowed to demonstrate (1) an ovarian origin based on elevated level of estradiol and of total proteins (100% specificity, 100% sensitivity); (2) urodigestive fistula based on the presence of high levels of digestive enzymes (cloaca in female fetuses or recto-urethral fistula in male fetuses); and (3) a renal origin (urinary pattern with low total proteins and absence of digestive enzymes); however, a biochemical pattern could not differentiate between fetal urogenital sinus and megacystis. CONCLUSION: Etiological diagnosis of a fetal cystic abdominal mass could impact both prenatal and postnatal management providing adapted prenatal counseling by a pediatric surgeon in surgically correctable congenital anomalies.