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

ABSTRACT: Congenital mesoblastic nephroma is an extremely rare, low-grade malignant renal tumor in children. A 10-month-old boy and a 4-month-old girl were admitted to our hospital with a huge abdominal mass. For staging of the mass, 18 F-FDG PET/CT and PET/MR were performed showing a huge heterogeneous abdominal mass accompanied by extensive heterogeneous aggregation. Both of them were highly suspected to be Wilms tumor, the most common renal malignant tumor in children. However, histopathological examination after surgery confirmed congenital mesodermal nephroma.

Severe neonatal hypercalcemia revealing congenital mesoblastic nephroma: A case report and management of neonatal hypercalcemia: Severe neonatal hypercalcemia revealing congenital mesoblastic nephroma.

Congenital mesoblastic nephroma is a rare pediatric renal tumor and has been reported in patients presenting with palpable abdominal mass, arterial hypertension, hematuria, polyuria, or hypercalcemia. Here we present the case of a 1-month-old neonate with suspected parathyroid hormone (PTH)-related peptide (PTH-rp)-mediated severe hypercalcemia revealing congenital mesoblastic nephroma. Preoperatively, hypercalcemia was corrected with hydration, furosemide, pamidronate, and low-calcium infant formula. Unilateral nephrectomy led to the resolution of hypercalcemia, transient hyperparathyroidism, and transient vitamin D and mineral supplementation. We conclude that congenital mesoblastic nephroma can secrete PTH-rp that can cause severe hypercalcemia.

Unusual Case of Concurrent Retroperitoneal Congenital Infantile Fibrosarcoma and Cellular Type Congenital Mesoblastic Nephroma.

BACKGROUND: Although congenital infantile fibrosarcoma (cIFS) is a rare soft tissue sarcoma among children, it constitutes one of the most common soft tissue sarcomas during the first year of life. Congenital mesoblastic nephroma (CMN) is the most common benign renal tumor usually developing during the first 3 months of life. cIFS and cellular type CMN (cCMN) share not only similar histopathologic features but identical molecular genetic abnormality including the ETV6/NTRK3 fusion gene. Here, we report an unusual case of cIFS occurring with cCMN. CASE PRESENTATION: An 18-month-old girl presented with a 1-month history of abdominal distension and a few days' history of a palpable abdominal mass. A large heterogenous mass sized 9.0×11.2×11.6 cm on the right side of the abdomen and an isolated heterogenous lesion sized 4×4.5 cm within the right kidney were noted from the imaging study. Pathologic findings were consistent with cIFS and cCMN of the right kidney. In addition, both pathologic specimens contained the ETV6/NTRK3 fusion gene. CONCLUSION: Although cIFS and cCMN share similar histopathologic features and molecular genetic abnormality, simultaneous occurrence of these 2 types of tumor is exceedingly rare. To our knowledge, this is the first unusual case report of concurrent cIFS and cCMN.

Congenital Mesoblastic Nephroma Presenting with Hematuria in a Neonate.

Congenital mesoblastic nephroma (CMN) is a rare tumor of infancy. CMNs can be histologically divided into classic, cellular, and mixed subtypes. Cellular CMNs are difficult to differentiate from Wilms tumors. Herein, a neonate with cellular CMN accompanied by macroscopic hematuria, is described. The clinical, pathological, and imaging features of the disease are discussed.

A rare cause of neonatal hypertension: Congenital mesoblastic nephroma.

Soyaltin E, Alaygut D, Alparslan C, Özdemir T, Arslansoyu-Çamlar S, Mutlubas F, Kasap-Demir B, Yavascan Ö. A rare cause of neonatal hypertension: Congenital mesoblastic nephroma. Turk J Pediatr 2018; 60: 198-200. A rare cause of neonatal hypertension: Congenital Mesoblastic Nephroma (CMN) is a rare renal tumor in childhood and has been reported with palpable abdominal mass, hypertension, hematuria, polyuria and hypercalcemia. Histopathologically it has been classified into two histological types: classic and cellular. We present a 32-week gestation infant and his histopathology reports of cellular CMN presented with refractory hypertension.

Management of mixed type congenital mesoblastic nephroma: Case series and review of the literature.

Congenital mesoblastic nephroma (CMN) is the most common renal tumor of infancy; however, it occurs infrequently with an incidence of 1 : 125,000. The cellular and classical variants are the most common subtypes of tumors, with a mixed variant occurring infrequently. We describe two cases of mixed variant CMN, which presented within days of each other differing in their clinical behavior. The first case followed a typical course, previously described in the literature, while the other deviated significantly. Traditionally, CMN presents as large abdominal mass in the neonatal period associated with a paraneoplastic syndrome, which can result in hypertension or hypercalcemia. Surgical resection is curative in most cases and long-term prognosis is excellent. Hypertension rarely persists after removal of the tumor, but remained in one of our two patients.

Congenital Mesoblastic Nephroma Presenting With Refractory Hypertension in a Premature Neonate: A Case Study.

The most common nonencapsulated solid renal tumor in the neonatal period is congenital mesoblastic nephroma. Mesoblastic nephroma is a solid lesion originating within or extending from the renal parenchyma. These tumors proliferate rapidly, typically within 3-6 months after birth. Mesoblastic nephromas are stratified by classification as either classical (benign) or atypical (malignant); masses composed of both benign and malignant cells are also reported. The hallmark clinical manifestation of mesoblastic nephroma is a palpable abdominal mass, which may be accompanied by hypertension, hypercalcemia, hematuria, and polyuria. Differentiating between benign and malignant renal tumors is essential to invoke a timely, evidence-based management and treatment plan. With appropriate surgical intervention in a timely manner, prognosis is excellent and mesoblastic nephroma is considered curable. We present a case involving a premature infant with congenital mesoblastic nephroma with discussion of embryology, pathophysiology, diagnostic, management, and prognostic implications for the neonate and family.

Congenital mesoblastic nephroma: Its diverse clinical features - A literature review with a case report.

To characterise congenital mesoblastic nephroma (CMN), with special emphasis on polyhydramnios and the neonatal prognosis, we summarise 31 CMN patients (30 reported patients and the present patient). CMN was detected at a median of 30 weeks' gestation, and infants were delivered at a median of 34 weeks' gestation. Of 27 patients with available data, 19 (70%) had polyhydramnios, of which 8 required amnio- drainage. Women with amnio-drainage gave birth significantly earlier (30.4 weeks' gestation) than those without polyhydramnios (36.7 weeks' gestation). Thus, CMN was frequently associated with polyhydramnios and this polyhydramnios was associated with a significant increase in the risk of preterm birth. Of 20 patients with available data, the affected-side kidney was 'compressed' in 16 and 'replaced' in 4: polyhydramnios was present in a half vs 100%, respectively, suggesting that a 'replaced' kidney may suggest a more aggressive tumour and may be associated with a poorer prognosis. Univariate analysis showed that early gestational week at diagnosis was the only feature significantly associated with poor prognosis. Thus, polyhydramnios, 'replaced' kidney and early gestational week at diagnosis, may indicate poor prognosis, to which obstetricians should pay attention.

Congenital Mesoblastic Nephroma Presenting With Hematuria in a Neonate: A Case Report.

Congenital mesoblastic nephroma (CMN) is the most frequent renal neoplasm of newborns and young infants. Four cases presenting with hemorrhagic manifestations have been reported in the English literature (Hu et al, 2006; Bolande et al, 1967). We report the unusual clinical and radiographic findings of a 2-day-old neonate with hematuria secondary to a CMN. The first ultrasound was equivocal. Repeat ultrasound followed by magnetic resonance imaging confirmed the diagnosis. He underwent a right nephroureterectomy with histopathology revealing a cellular variant of CMN without classical translocation (t12:15). Neonates presenting with hematuria require close follow-up and serial imaging to rule out occult renal tumors. Classical translocation may not be demonstrable in all the cases.

Maternal manifestation of Ballantyne's syndrome occurring concomitantly with the development of fetal congenital mesoblastic nephroma.

Various fetal or placental disorders cause Ballantyne's (mirror) syndrome. For the first time, we report a maternal manifestation of Ballantyne's syndrome occurring concomitantly with the development of fetal congenital mesoblastic nephroma (CMN). In a pregnant woman with a CMN fetus, lung edema, hypertension, hyperthyroidism, and high serum human chorionic gonadotrophin level occurred, all of which characterize maternal manifestation of Ballantyne's syndrome. The fetus and placenta were devoid of 'edema', lacking 'triple edema', and thus this condition was not diagnosed as Ballantyne's syndrome; however, we considered this condition as the maternal manifestation of Ballantyne's syndrome. We performed emergent cesarean section at 28 weeks. Delivery acutely ameliorated maternal symptoms. Tumor was resected and was confirmed as CMN. Maternal manifestations of Ballantyne's syndrome, such as lung edema and hypertension, can occur in a mother with fetal CMN even without fetal and/or placental edema. The clinical course of this patient may suggest an etiology of Ballantyne's syndrome.

Parathyroid-hormone-related protein-mediated hypercalcemia in benign congenital mesoblastic nephroma.

Parathyroid hormone-related protein (PTHrP) mediated hypercalcemia of malignancy is rare in children, and even more so in the setting of a benign tumor. We report two infants with PTHrP-mediated hypercalcemia secondary to congenital mesoblastic nephroma and their outcome after removal of the benign tumor. Pre-operatively hypercalcemia was corrected with saline hydration, furosemide, calcitonin and/ or pamidronate. Following resection of the tumor serum PTHrP normalized. Immunohistochemical staining of tumor cells was positive for PTHrP. Post-operatively the infants developed elevated serum parathyroid hormone with low- normal serum Ca and P, and undetectable urinary Ca and P, probably due to their movement into bone. Children needed treatment with calcitriol, Ca and P supplementation for 6-12 weeks until PTH normalized and urinary Ca and P were detected, suggesting bone replenishment. We conclude that benign congenital mesoblastic nephroma can secrete PTHrP that can cause severe hypercalcemia; and following excision one should anticipate the development of a transient modified "hungry bone"-like condition requiring Ca, P and calcitriol therapy for several weeks accompanied by careful monitoring of mineral homeostasis.

Congenital mesoblastic nephroma presenting with massive hematuria and hemorrhagic shock: report of one case.

Congenital mesoblastic nephroma (CMN) is a rare benign tumor that occurs during the neonatal period and early infancy. The vast majority of these tumors present as asymptomatic palpable abdominal masses. We describe an unusual presentation of a CMN in a 10-month-old male infant who presented with massive hematuria and the development of hemorrhagic shock. Abdominal ultrasound showed a heterogeneous solid complex mass measuring 4.8 x 3.5 cm arising from the upper pole of the left kidney. The patient was resuscitated using intravenous fluids and blood transfusions because persistent massive bloody urine leading to progressive shock occurred the night of the admission day. Preoperative diagnosis was possible Wilms tumor of the left kidney. The histopathological findings were consistent with the character of a cellular variant of CMN. The patient was free of recurrence and metastasis at the 2-year follow-up examination. Our case report suggests that CMN is a rare benign renal tumor during infancy and may present with unusual massive hematuria and shock.

The outcome of prenatally diagnosed renal tumors.

PURPOSE: We assessed the incidence of perinatal morbidity and evaluated the outcome in children with prenatally diagnosed renal tumors in a retrospective multicenter study. MATERIALS AND METHODS: A review of the records of patients from 20 institutions identified 28 children with prenatally diagnosed renal tumors. Prenatal findings, clinical charts, and radiological, surgical and pathological reports were reviewed in this study. RESULTS: There were 26 congenital mesoblastic nephromas and 2 Wilms tumors. One or more complications were identified in 20 of the 28 cases (71%) during the perinatal period. Polyhydramnios was observed in 11 fetuses (39%), 2 presented with hydrops fetalis and 7 presented in acute fetal distress requiring emergency cesarean section, of which 1 died in utero before delivery. Median gestational age of the 27 neonates born alive was 35 weeks (range 29 to 39), including 13 (46%) who were pre-term (less than 34 weeks of gestation). Complications at birth included hemodynamic instability in 3 newborns, of whom 2 underwent emergency surgery, respiratory distress syndrome in 8 (30%) and hypertension in 6 (22%). Surgical complications occurred in 7 patients (26%), including tumor rupture in 1 and intraoperative bleeding with postoperative death in 1. At a median followup of 42 months (range 2 to 105) 26 of the 27 children were in complete remission. CONCLUSIONS: Fetal renal tumors have an excellent oncological outcome but a high risk of perinatal complications. Prenatal diagnosis should allow planning the delivery at a pediatric tertiary care center to avoid a potentially life threatening condition in neonates in the first hours of life.

Cellular congenital mesoblastic nephroma with contralateral medullary nephrocalcinosis.

Congenital mesoblastic nephroma is the most common renal mass in the newborn period and can present with atypical findings. Certain associated conditions such as hypercalcaemia, hypertension and reninism have been described. We report a cellular variant of congenital mesoblastic nephroma with hypercalcaemia and contralateral medullary nephrocalcinosis.

Renal tumors in infants less than 6 months of age.

BACKGROUND/PURPOSE: Renal tumors are rare in infants less than 6 months of age and may have associated paraneoplastic symptoms. To better define the characteristics of these tumors the authors reviewed their 10-year institutional experience. METHODS: The authors searched the pathology database to identify all renal tumors resected at their institution since 1992 (after IRB approval and guidelines). The clinical presentation, operative details, pathology, and outcome for all children < or = 6 months of age were reviewed. RESULTS: Of 101 children who had renal tumors resected during this period, 11 (11 %) were 6 months of age or less. Histopathologic examination showed congenital mesoblastic nephroma (CMN) in 7 patients (4 with cellular features), Wilms' tumor in 3 patients, and ossifying renal tumor of infancy in 1. Renal masses were detected antenatally in 2 patients and during newborn examination in 1 patient; however, the mean age at diagnosis was 72 +/- 18 days. Ten children had a palpable abdominal mass, 3 had gross hematuria, and 6 had hypertension (4 CMN; 2 Wilms'). Only 1 child had hypercalcemia (cellular CMN). Ten infants had nephroureterectomy, and 1 had a partial nephrectomy. All patients had either stage I or II disease. At follow-up (mean 4.2 +/- 1.2 years) 10 patients are alive with no evidence of disease. One newborn with hydrops and a very large congenital Wilms' tumor had abdominal compartment syndrome and died during surgery. CONCLUSIONS: About 10% of renal masses may occur in infants less than 6 months of age. Although mesoblastic nephroma is the most common renal tumor in this age group, Wilms' tumor also may be seen. Paraneoplastic syndromes, such as hypertension and hypercalcemia, are common in these infants and are not specific for tumor type. These tumors generally present at an early stage and have an excellent prognosis overall.

Prenatal diagnosis of congenital mesoblastic nephroma associated with renal hypertension in a premature child.

In the present article, we report, for the first time, a prenatal diagnosis of a congenital mesoblastic nephroma in combination with a post-partum hyperreninemia with hypertension. A newborn was delivered at 35 weeks gestation who had an intrauterine diagnosis of a renal mass as early as 32 weeks gestational age by ultrasound examination. Tumor nephrectomy was performed on day 11 after delivery when an increase in hypertension was observed in the newborn.