Elevated levels of aldosterone in the amniotic fluid in two cases of congenital mesoblastic nephroma

Abstract

We report two cases of congenital mesoblastic nephroma (CMN) in which there were elevated levels of aldosterone in the amniotic fluid in comparison with control cases with polyhydramnios but without CMN. The progression of fetal hydrops due to high-output cardiac failure was also detected in both cases. In the first case, a 37-year-old woman was referred at 30 weeks' gestation owing to the presence of a fetal abdominal mass. The tumor showed hypervascularity (Figure 1a) with a feeding vessel (Figure 1b). The four-quadrant amniotic fluid index (AFI) was 55.2 cm, and amnioreduction (removal of 2 L each time) was performed three times over the course of about 3 weeks. During this period, the cardiothoracic area ratio (CTAR) and preload index deteriorated from 35 to 45% and from 0.43 to 0.64, respectively. Fetal scalp edema also increased from 2.0 to 6.7 mm. Aldosterone levels in the amniotic fluid were found to be high in comparison with controls (385 pg/mL at 30 + 1 weeks vs. mean of 143.7 (range, 52.4–245) pg/mL in five age-matched controls with polyhydramnios). Ultrasound imaging in two cases of congenital mesoblastic nephroma. (a,b) Case 1. (a) Doppler image at 31 + 6 weeks' gestation showing that the mass (M) had high vascularity. (b) Pulsed Doppler image demonstrating that the tumor feeding vessel was an artery. LK, left kidney. (c,d) Case 2. (c) Ultrasound image at 29 weeks' gestation showing fetal scalp edema (arrows). (d) The end-diastolic velocity flow of the umbilical artery was reversed (arrows). After the pharmacological induction of pulmonary maturity at 32 weeks' gestation, premature rupture of membranes occurred spontaneously at 32 + 5 weeks and a male infant weighing 2652 g (1- and 5-min Apgar scores 3 and 6, respectively) was delivered by emergency Cesarean section (owing to a history of previous Cesarean section). A nephrectomy was performed on day 4 after birth because of uncontrolled hypertension. The serum reactive renin and aldosterone levels before surgery were 1400 (mean ± SD in normal neonates, 175 ± 156) pg/mL and 3501 (mean ± SD in normal neonates 626.6 ± 48.5) pg/mL, respectively, but the level of reactive renin after the operation had decreased to 7.56 pg/mL and that for aldosterone had decreased to 1485 pg/mL, in conjunction with stabilization of blood pressure. Follow-up at 4 years identified no recurrence. In the second case, a 35-year-old woman was referred at 25 weeks' gestation and her fetus was diagnosed as having CMN. The AFI was 43.1 cm, and amnioreduction (2 L each time) was performed four times. Aldosterone levels in the amniotic fluid were again found to be high in comparison to controls (374 pg/mL at 26 + 4 weeks). At 29 weeks' gestation, CTAR was 40%, and fetal scalp edema was 8.0 mm (Figure 1c). Moreover, the end-diastolic flow of the umbilical artery was reversed (Figure 1d). After induction of pulmonary maturity, a male weighing 1754 g (1- and 5-min Apgar scores 4 and 6, respectively) was delivered by Cesarean section. Serum aldosterone level was 4000 pg/mL. Nephrectomy was performed 2 days after delivery because of decreased perfusion to the brain secondary to vascular steal phenomenon. Unfortunately, the infant died because of blood loss due to surgical complications during resection of the highly vascular tumor. CMN is generally a benign tumor with a favorable prognosis following surgical resection. However, CMN associated with non-immune fetal hydrops, which is rare, is lethal for the fetus. All five cases previously reported have been fatal1-4, and immediate delivery is recommended2. The pathophysiology of hydrops accompanying CMN remains unknown, but is likely to be caused by high-output heart failure due to vascular shunting in cases with an angiomatous tumor1. This is the first report of elevated levels of aldosterone in the amniotic fluid in CMN cases with developing hydrops, followed by postpartum hyper-reninemia with hypertension5, 6. The calculation of a combined cardiac output would also be effective for the timely detection of the risk of hydrops in fetuses with highly vascular tumors7, 8. We suggest that, following the prenatal diagnosis of CMN, it would be useful to measure aldosterone levels in the amniotic fluid in conjunction with monitoring of cardiac function in order to detect those rare cases with a poor prognosis. T. Kotani*, S. Sumigama*, H. Hayakawa , Y. Mano , H. Tsuda , C. Sugiyama , F. Kawachi , M. Hironaka , T. Kato , K. Kaneko§, M. Hayakawa*, F. Kikkawa , * Maternity and Perinatal Care Center, Nagoya University Hospital, Nagoya, Japan, Department of Obstetrics and Gynecology, Nagoya Graduate University School of Medicine, Nagoya, Japan, Department of Pediatrics, Nagoya Graduate University School of Medicine, Nagoya, Japan, § Department of Pediatric Surgery, Nagoya Graduate University School of Medicine, Nagoya, Japan