Prenatal diagnosis of congenital mesoblastic nephroma

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

Background

Congenital mesoblastic nephroma is the most common renal tumor in children under the age of 6 months, comprising 3-10% of all kidney tumors in children. It is a rare and mostly benign tumor. It divides into cellular, classic, and mixed subtypes. It is typically detected in the third trimester of pregnancy using ultrasonography and magnetic resonance imaging. The best treatment is surgically by completely removing the tumor.

Case presentation

We reported a case of a one-day-old female who was born at 31 weeks gestation weighing 1670 g. Preterm labor was due to polyhydramnios, which was diagnosed predelivery. A large mass was detected in the left hypochondrium using computerized tomography, total nephrectomy was performed, and the histopathological examination of the specimen confirmed the diagnosis of congenital mesoblastic nephroma.

Clinical discussion and conclusion

Early polyhydramnios could be the most significant sign of renal tumors in infants, especially congenital mesoblastic nephroma.

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

BACKGROUND

Tumors are rare in neonatal age. Congenital mesoblastic nephroma (CMN) is a usually benign renal tumor observed at birth, or in the first months of life. It may also be identified prenatally and associated with polyhydramnios leading to preterm delivery. Effective treatment is surgical in most cases, consisting in total nephrectomy. In literature, very few studies report on the neonatal management of such a rare disease, and even less are those describing its uncommon complications.

CASES PRESENTATION

We report on two single-center newborns affected with CMN. The first patient is a preterm female baby, born at 30+ 1 weeks of gestation (WG) due to premature labor, with prenatal (25 WG) identification of an intra-abdominal fetal mass associated with polyhydramnios. Once obtained the clinical stability, weight gain, instrumental (computed tomography, CT, showing a 4.8 × 3.3 cm left renal neoformation) and histological/molecular characterization of the lesion (renal needle biopsy picture of classic CMN with ETV6-NTRK3 translocation), a left nephrectomy was performed at 5 weeks of chronological age. The following clinical course was complicated by intestinal obstruction due to bowel adherences formation, then by an enterocutaneous fistula, requiring multiple surgical approaches including transitory ileo- and colostomy, before the conclusive anastomoses intervention. The second patient is a 17-day-old male term baby, coming to our observation due to postnatal evidence of palpable left abdominal mass (soon defined through CT, showing a 7.5 × 6.5 cm neoformation in the left renal lodge), feeding difficulties and poor weight gain. An intravenous diuretic treatment was needed due to the developed hypertension and hypercalcemia, which regressed after the nephrectomy (histological diagnosis of cellular CMN with ETV6-NTRK3 fusion) performed at day 26. In neither case was chemotherapy added. Both patients have been included in multidisciplinary follow-up, they presently show regular growth and neuromotor development, normal renal function and no local/systemic recurrences or other gastrointestinal/urinary disorders.

CONCLUSIONS

The finding of a fetal abdominal mass should prompt suspicion of CMN, especially if it is associated with polyhydramnios; it should also alert obstetricians and neonatologists to the risk of preterm delivery. Although being a usually benign condition, CMN may be associated with neonatal systemic-metabolic or postoperative complications. High-level surgical expertise, careful neonatological intensive care and histopathological/cytogenetic-molecular definition are the cornerstones for the optimal management of patients. This should also include an individualized follow-up, oriented to the early detection of any possible recurrences or associated anomalies and to a better quality of life of children and their families.

Assessment of Amniotic Fluid Volume in Pregnancy

Amniotic fluid (AF) is an integral part of the fetal environment and is essential for fetal growth and development. Pathways of AF recirculation include the fetal lungs, swallowing, absorption through the fetal gastrointestinal tract, excretion through fetal urine production, and movement. In addition to being a marker for fetal health, adequate AF is necessary for fetal lung development, growth, and movement. The role of diagnostic imaging is to provide a detailed fetal survey, placental evaluation, and clinical correlation with maternal conditions to help identify causes of AF abnormalities and thereby enable specific therapy. Oligohydramnios prompts evaluation for fetal growth restriction as well as genitourinary issues, including renal agenesis, multicystic dysplastic kidneys, ureteropelvic junction obstruction, and bladder outlet obstruction. Premature preterm rupture of membranes should also be clinically excluded as a cause of oligohydramnios. Clinical trials evaluating amnioinfusion are underway as a potential intervention for renal causes of oligohydramnios. Most cases of polyhydramnios are idiopathic, with maternal diabetes being a common cause. Polyhydramnios prompts evaluation for fetal gastrointestinal obstruction and oropharyngeal or thoracic masses, as well as neurologic or musculoskeletal anomalies. Amnioreduction is performed only for maternal indications such as symptomatic polyhydramnios causing maternal respiratory distress. Polyhydramnios with fetal growth restriction is paradoxical and can occur with maternal diabetes and hypertension. When these maternal conditions are absent, this raises concern for aneuploidy. The authors describe the pathways of AF production and circulation, US and MRI assessment of AF, disease-specific disruption of AF pathways, and an algorithmic approach to AF abnormalities. ^©RSNA, 2023 Online supplemental material is available for this article. Quiz questions for this article are available through the Online Learning Center.

Enlarged Abdominal Lymph Node as a Cause of Polyhydramnios in the Course of Congenital Neonatal Leukaemia: A Case Report and Review of the Literature on Foetal Abdominal Tumours with Coexisting Polyhydramnios

Polyhydramnios represents a complication found in 0.2–2% of pregnancies, and it is usually diagnosed between 31 and 36 weeks of pregnancy. Although most cases of polyhydramnios are idiopathic, maternal diabetes or foetal malformations constitute frequent causes of the excessive accumulation of the amniotic fluid. Considering the latter, polyhydramnios may rarely be caused by foetal abdominal tumours, with the incidence rate of 2–14 cases per 100,000 live births. Congenital neonatal leukaemia (CNL) is a rare disease with a reported incidence rate of 5–8.6 cases per million live births. In the prenatal period, the ultrasound abnormalities associated with CNL include hepatomegaly and splenomegaly. In this paper, we presented a case of polyhydramnios caused by mechanical pressure on the foetal gastrointestinal tract by an enlarged lymph node in the course of CNL, as well as reviewing the available literature on foetal abdominal tumours with concurrent polyhydramnios.

Use of Calcitonin for Hypercalcemia in a Premature Neonate With Congenital Mesoblastic Nephroma

We report on a premature neonate (31 4/7 weeks' gestation) who presented with hypercalcemia secondary to congenital mesoblastic nephroma (CMN), the most common type of renal tumor in neonates. Typical presentation includes a palpable abdominal mass or swelling and may include abdominal pain, hematuria, fever, or hypertension. A less common complication of CMN is hypercalcemia of malignancy. Although the primary management strategy for hypercalcemia of malignancy is to treat the underlying disease, there are several agents that can be used as well for acute hypercalcemia including fluids, loop diuretics, corticosteroids, bisphosphonates, and calcitonin. However, there is minimal evidence to guide efficacious and safe treatment selection and dosing as hypercalcemia is a rare complication of this tumor type. This case adds to the current body of literature as only the second case of parathyroid hormone-related peptide-mediated hypercalcemia in a preterm neonate treated with calcitonin and is the first to specify a successful dose escalation strategy of calcitonin for this indication.

Prenatal Course and Sonographic Features of Congenital Mesoblastic Nephroma

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.

Neonatal congenital mesoblastic nephroma that caused respiratory oncologic emergency early after birth: a case report

BACKGROUND

Congenital mesoblastic nephromas mainly present as asymptomatic abdominal masses, but some present hematuria, hypertension or hypercalcemia. Neonatal dyspnea in an early-birth neonate due to rapid tumor growth is reported here for the first time.

CASE PRESENTATION

A renal tumor and polyhydramnios were detected by ultrasonography of a male fetus at 32 weeks and 3 days of gestation. The mother had abdominal distension due to the polyhydramnios and signs of imminent premature birth. Amniocentesis was performed and the signs of imminent preterm birth subsided, but growth of the renal tumor was noted as a potential cause of respiratory dysfunction. Cesarean section was performed at 36 weeks and 2 days of gestation. His birthweight was 2638 g and his 1 and 5 min APGAR scores were 2 and 4 points, respectively. There was no spontaneous breathing at birth and he had remarkable abdominal distention. He underwent cardiopulmonary resuscitation. After circulation stabilized, emergency surgery was performed because of progressive hypoxemia and respiratory acidosis. Laparotomy revealed a huge tumor arising from the right kidney and right nephrectomy was performed. Histopathological examination led to diagnosis of congenital mesoblastic nephroma. The respiratory condition and circulatory dynamics stabilized after the pressure on the thorax from the tumor was relieved by surgery. The postoperative course was uneventful. No recurrence or complications have been observed in the 36 months since the surgery.

CONCLUSIONS

Congenital mesoblastic nephroma can rapidly increase in size from the fetal period and may cause respiratory oncologic emergency, although there is relatively good prognosis.

Prenatal diagnosis of fetal congenital mesoblastic nephroma by ultrasonography combined with MR imaging: A case report and literature review

RATIONALE

Fetal congenital mesoblastic nephroma (CMN) is a rare renal tumor, characterized by polyhydramnios, premature birth, and neonatal hypertension. In the prenatal stage, it is particularly difficult to diagnose CMN either by ultrasonography or magnetic resonance imaging (MRI). Thus, CMN is frequently detected in the third trimester in the clinical scenario.

PATIENT CONCERNS

A 29-year-old G2P0 pregnant woman took routine prenatal examinations in our hospital. The fetal right kidney abnormality was not observed after 2 systematical ultrasonic examinations (at 24 and 31 weeks of gestation respectively), and only an increase was noticed in the amniotic fluid index (from 19.3 to 20.8 cm).

DIAGNOSIS

CMN was detected by antenatal ultrasonography and MRI as a fetal right renal mass at 35 weeks of gestation in our hospital.

INTERVENTIONS

The pregnant woman was admitted at a gestational age of 38 weeks and 5 days due to alterations in renal function. Further, the pregnant woman was administered with "oxytocin" to promote delivery, and the neonate underwent a right nephrectomy on the 9th day after birth.

OUTCOMES

The pathological examination confirmed a cellular type of right CMN. The neonate recovered well after operation without adjuvant treatment. During 6 months of follow-up, the neonate grew well and showed no signs of recurrence or metastasis.

CONCLUSION

Polyhydramnios detected during prenatal examination required attention due to the risk of malformation of fetal urinary system. Prenatal ultrasonography combined with MRI could not only clearly identify the origin of the tumor, but also distinguish the correlation between the tumor and adjacent structures, thereby leading to early diagnosis and favorable prognosis.

Papers presented at the fall 2020 Pediatric Urologic Oncology Work Group of the Societies of Pediatric Urology meetingPrenatally Diagnosed Solid Renal Mass

Congenital mesoblastic nephroma is the most common renal neoplasm diagnosed in the first month of life of which 15% occur prenatally. We present a prenatal diagnosis of a 5.8 cm solid renal mass identified on the 36-week ultrasound. Labor was induced at 38 weeks and a female infant was delivered vaginally without complications. The postnatal ultrasound demonstrated a 6.3 cm heterogeneous mass nearly replacing the kidney. The infant underwent a radical nephrectomy on the first day of life and pathology confirmed stage II classic CMN with negative margins and nodes. She is otherwise healthy at follow-up of 1 year with no evidence of recurrence.

Management of fetal tumors

In this review article, we discuss the most common fetal tumors, their prenatal management, and outcomes. Overall, the most important outcome predictors are tumor histology, size, vascularity, and location. Very large lesions, lesions causing cardiac failure, and hydrops and lesions obstructing the fetal airway have the poorest outcome, as they may cause fetal death or complications at the time of delivery. Fetal therapy has been developed to improve outcomes for the most severe cases and can consist of transplacental therapy (sirolimus for rhabdomyomas or steroids for hemangiomas and microcystic lung lesions) or surgical intervention (shunting of cystic masses, tumor ablation, occlusion of blood flow or airway exploration, and protection). Given the rarity of fetal tumors, patients should be referred to expert centers where care can be optimized and individualized to allow the best possible outcomes.