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

Abstract

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.

Poor outcome in congenital mesoblastic nephroma with TPM3::NTRK1 fusion: a case report from multi-disciplinary treatment to molecular tumor board

“…Currently, for patients with a confirmed diagnosis of CMN, early surgery can achieve desirable treatment outcomes. Numerous clinical studies have proven this conclusion ( 1 - 6 ), which is also the advantage of early surgery. However, for patients with an unclear diagnosis, the decision to proceed with surgical treatment still needs to be approached cautiously.…”

“…Congenital mesoblastic nephroma (CMN) is a rare low-grade malignant kidney tumor in infants younger than 3 months, accounting for up to 87% of all renal tumors in the first 2 months of life ( 1 - 3 ). About 90% of children with CMN present with an abdominal mass and hematuria by their first birthday ( 4 , 5 ).…”

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

“…Complete surgical resection is performed in the first week to treat CMN patients 9 . Patients older than 3 months at diagnosis with stage III, cellular or mixed subtype, or incomplete resection are more likely to experience recurrence and metastases 3 , 10 , 11 . Adjuvant chemotherapy is advised for such conditions 12 .…”

“…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 .…”