Prenatal Course and Sonographic Features of Congenital Mesoblastic Nephroma

Abstract

Background: Congenital mesoblastic nephroma (CMN) is the most common renal tumor among fetuses and infants before the age of 6 months. It usually behaves as a benign tumor. The prenatal features and outcomes of pregnancies with fetal CMN have never been systematically reviewed and analyzed, whereas neonatal or pediatric series have been published several times. The aims of this study are to (1) describe the prenatal natural course and prenatal sonographic char-acteristics of CMN; (2) determine the outcomes of pregnancies with fetal CMN; and (3) demonstrate typical sonographic images together with video clips of prenatal CMN, as an educational example based on our index case presented here. Methods: Studies focused on fetal CMN, including those consecutively published on PubMed from 1980 to June 2022 as well as the index case presented here, were identified and validated to perform a systematic review. The data of fetal imaging and the prenatal course of pregnancies were extracted for analysis. Results: The findings derived from 41 cases of review are as follows: (1) No single case has been diagnosed in the first half of pregnancy. No cases were detected during routine anomaly screening at mid-pregnancy. All cases were de-tected in the third trimester or late second trimester. (2) Polyhydramnios is very common and is the first clinical manifestation in most cases, leading to detailed ultrasound in the second half of pregnancy. (3) Preterm birth and low birth weight are the most common adverse pregnancy out-comes, resulting in neonatal morbidity. (4) Hydrops fetalis, though relatively rare, can be associated with CMN and is a grave sign. (5) Prenatal diagnosis is essential since it is critical for the antenatal plan, comprising either referral to a tertiary care center or proper surveillance to prevent serious obstetric complications, especially preterm birth. (6) Ultrasound is the primary tool for prenatal diagnosis of CMN, whereas MRI can be used as an adjunct if some other tumors are suspicious or sonographic features are not typical for CMN. Conclusion: In contrast to CMN in neonates, fetal CMN is much more serious since it significantly impacts adverse pregnancy outcomes and perinatal morbidity and mortality. The typical prenatal course and the sonographic features of CMN are described.

A massive primary congenital mesoblastic nephroma was successfully managed through open total nephrectomy: a case report

“…The majority of tumors are benign and connected to multicystic dysplasia and hydronephrosis. Until the age of 6 months, CMN is the most prevalent kidney tumor in fetuses and newborns 2 . A significant increase in tumor size occurred in the third trimester when practically all fetal CMN cases were discovered.…”

“…Congenital renal tumors are uncommon neoplasms, including congenital mesoblastic nephroma (CMN) 1 . It is a rare pediatric kidney tumor that represents 3–10% of all pediatric renal neoplasms and peaks in incidence during the first 3 postnatal months 2 . The first definitive sign that a renal lesion is present is polyhydramnios, which causes preterm delivery 3 .…”

“…Ultrasonography (US) can only identify 11–14% of cases 4 . This tumor may lead to major complications such as polyhydramnios, neonatal hypertension, preterm labor, and hydrops fetalis 2 . The treatment of choice is surgical resection 1 .…”

Congenital Mesoblastic Nephroma Mimic Wilms Tumor on 18F-FDG PET/CT and PET/MR

“…2 The typical clinical manifestation is abdominal mass, which may be accompanied by hypertension, hematuria, polyuria, or hypercalcemia. 3 Prenatal diagnosis depends on ultrasound, 4 and postpartum diagnosis can rely on ultrasound, CT, and MRI. Both 2 cases showed a huge mass in the abdomen with uneven signal, and 18 F-FDG is highly aggregated in the solid component and low uptake in the cystic part.…”

Report and follow-up on two new patients with congenital mesoblastic nephroma

“…No specific ultrasonographic features allow CMN differentiation from other renal neoformations. Actually, the most suggestive aspect is its appearance in the fetal period, which is less frequent in other renal neoplasms [ 4 – 6 ]. Some additional information could be provided by fetal Magnetic Resonance Imaging (MRI), which however is not part of the routine diagnostic work-up [ 4 , 7 , 8 ].…”