Prenatal diagnosis of congenital mesoblastic nephroma in mid-second trimester by sonography and magnetic resonance imaging

Diagnostic magnetic resonance imaging characteristics of congenital mesoblastic nephroma: a retrospective multi-center International Society of Pediatric Oncology-Renal Tumor Study Group (SIOP-RTSG) radiology panel study

BACKGROUND

Congenital mesoblastic nephroma is the most common solid renal tumor in neonates. Therefore, patients <3 months of age are advised to undergo upfront nephrectomy, whereas invasive procedures at diagnosis in patients ≥3 months of age are discouraged by the International Society of Pediatric Oncology-Renal Tumor Study Group (SIOP-RTSG). Nevertheless, discriminating congenital mesoblastic nephroma, especially from the more common Wilms tumor, solely based on imaging remains difficult. Recently, magnetic resonance imaging (MRI) has become the preferred modality. Studies focusing on MRI characteristics of congenital mesoblastic nephroma are limited.

OBJECTIVE

This study aims to identify diagnostic MRI characteristics of congenital mesoblastic nephroma in the largest series of patients to date.

MATERIALS AND METHODS

In this retrospective multicenter study, five SIOP-RTSG national review radiologists identified 52 diagnostic MRIs of histologically proven congenital mesoblastic nephromas. MRI was performed following SIOP-RTSG protocols, while radiologists assessed their national cases using a validated case report form.

RESULTS

Patients (24/52 classic, 11/52 cellular, and 15/52 mixed type congenital mesoblastic nephroma, 2/52 unknown) had a median age of 1 month (range 1 day-3 months). Classic type congenital mesoblastic nephroma appeared homogeneous with a lack of hemorrhage, necrosis and/or cysts, showing a concentric ring sign in 14 (58.3%) patients. Cellular and mixed type congenital mesoblastic nephroma appeared more heterogeneous and were larger (311.6 and 174.2 cm3, respectively, versus 41.0 cm3 for the classic type (P<0.001)). All cases were predominantly T2-weighted isointense and T1-weighted hypointense, and mean overall apparent diffusion coefficient values ranged from 1.05-1.10×10-3 mm2/s.

CONCLUSION

This retrospective international collaborative study showed classic type congenital mesoblastic nephroma predominantly presented as a homogeneous T2-weighted isointense mass with a typical concentric ring sign, whereas the cellular type appeared more heterogeneous. Future studies may use identified MRI characteristic of congenital mesoblastic nephroma for validation and for exploring the discriminative non-invasive value of MRI, especially from Wilms tumor.

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.

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.

Cellular congenital mesoblastic nephroma detected by prenatal MRI: a case report and literature review

Congenital mesoblastic nephroma (CMN) is a rare tumor, yet it is the most frequently diagnosed renal neoplasm in the first 3 months of life. CMN reports with prenatal magnetic resonance imaging (MRI) are scarce. Our aims were to describe a case with fetal MR imaging along with other findings, and to review the literature concerned with prenatal MRI detection of CMN. Upon routine ultrasound (US) examination of a 36-week pregnant woman, a fetal abdominal mass was disclosed. Prenatal MRI revealed a large, well-circumscribed renal mass of solid and cystic components, not invading the adjacent tissues, but compressing normal renal parenchyma of the lower pole of the left kidney. Thus, a low malignant renal tumor was considered. After Cesarean delivery, imaging including US and computerized tomography (CT) scan was performed on the apparently healthy boy and verified the prenatal MRI finding. Accordingly, left nephrectomy was performed at the age of 12 days. The pathology confirmed CT results of the solid and cystic components of the mass, in addition to the necrotic and hemorrhagic constitution. Cellular CMN was diagnosed, and ETV6 gene rearrangement was demonstrated by FISH analysis. No recurrence was detected within the 40 months follow-up after the operation. Our report described a rare and seldomly detected renal tumor in utero with the aid of MRI and reviewed the few related reports in the literature in which MRI was performed prenatally. This report also highlights the need for prenatal MRI as a complementary tool to US in cases with suspected fetal renal mass and recommends its use for carefully managing the possible risks during the perinatal period.

Prenatal diagnosis and postnatal management of congenital mesoblastic nephroma: Experience at a single center in China

OBJECTIVE

To review the prenatal and postnatal clinical characteristics and pathological subtypes, as well as the surgical outcome for congenital mesoblastic nephroma (CMN) cases.

METHOD

A retrospective review was performed in 11 cases with CMN prenatally diagnosed at a single center between 2015 and 2019. The clinical characteristics, surgical outcome, histopathology, and follow-up were retrospectively obtained and reviewed.

RESULTS

The median gestational age at which the sonographic diagnosis was made was 35 weeks. Polyhydramnios was found in four (36.4%) cases, and all resulted in a preterm birth. Nine infants had hypertension. Ten cases underwent radical nephrectomy, and one underwent radical nephrectomy and partial adrenalectomy. The pathological results showed that six tumors were classical variants, four mixed variants, and one was a cellular variant. Three cases presented as a stage I, eight as stage II, and no stage III or IV cases were diagnosed. All patients are alive so far. At a median follow-up of 14 months, no local recurrence, or remote metastases were found.

CONCLUSION

The prognosis of prenatal CMN cases is excellent after early surgery.

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.

Prenatal Diagnosis of Fetal Congenital Mesoblastic Nephroma and Neonatal Follow-up

We describe a case of fetal congenital mesoblastic nephroma (CMN) who was diagnosed with ultrasound at 32 weeks of gestation; after delivery, the neonate received left radical nephrectomy, and pathology report confirmed the diagnosis. All cross-sectional imaging studies, such as ultrasonography, computed tomography (CT) scanning, and magnetic resonance imaging, may help to define the organ of origin and the relationship to the ipsilateral kidney. To our knowledge, this is the first case of fetal CMN who was diagnosed in the third trimester and then with a live-born baby in Taiwan. The prenatal examination such as three-dimensional ultrasound and CT image was performed to help us for prenatal diagnosis.

Renal Tumors of Childhood: Radiologic-Pathologic Correlation Part 1. The 1st Decade: From the Radiologic Pathology Archives

Wilms tumor is the second most common pediatric solid tumor and by far the most common renal tumor of infants and young children. As most tumors are large at presentation and are treated with nephrectomy, the role of imaging is primarily in preoperative planning and evaluation for metastatic disease. However, with treatment protocols increasingly involving use of preoperative (neoadjuvant) chemotherapy (the standard in Europe) and consideration of nephron-sparing surgery, the role of imaging is evolving to include providing initial disease staging information and a presumptive diagnosis to guide therapy. Differential diagnostic considerations include lesions that are clinically benign and others that require more intensive therapy than is used to treat Wilms tumor. In part 1 of this article, the unique histologic spectrum of renal neoplasms of infants and young children is reviewed with emphasis on radiologic-pathologic correlation. Part 2 will focus on renal tumors of older children and adolescents.

Prenatal diagnosis of congenital mesoblastic nephroma

Congenital mesoblastic nephroma is a rare renal tumor that is diagnosed during pregnancy and is associated with polyhydramnios, prematurity, and neonatal hypertension. Differential diagnoses include Wilms tumor, adrenal neuroblastoma, and other abdominal tumors. We report a case of congenital mesoblastic nephroma detected by prenatal ultrasonography as a large fetal renal mass with polyhydramnios at 32 weeks of gestation. Ultrasonography showed a 6×6-cm complex, solid, hyperechoic, round mass in the right kidney. At 35 weeks of gestation, the patient was admitted with preterm premature rupture of membranes and the baby was delivered vaginally. Postnatal ultrasonography and computed tomography showed a heterogeneous solid mass on the right kidney. At the end of the first week of life, a right nephrectomy was performed and subsequent pathological examination confirmed a cellular variant of congenital mesoblastic nephroma with a high mitotic count. Postoperative adjuvant chemotherapy was administered. The newborn was discharged in good condition.

Prenatal sonographic diagnosis of multicystic congenital mesoblastic nephroma

The authors report an unusual presentation of congenital mesoblastic nephroma as a multilocular cystic renal lesion. Prenatal sonography revealed a unilateral, encapsulated, multilocular cystic mass with solid components measuring 5.7 × 5.4 × 4.3 cm in the left renal fossa. There was no increase in vascularity and no signs of hydrops fetalis. On the forth postnatal day left-sided radical nephrectomy was performed and histopathological examination revealed cellular type congenital mesoblastic nephroma. A multicystic appearance is rare as the vast majority of prenatally diagnosed congenital mesoblastic nephroma cases presented in the literature are of the classic type with solid homogenous or heterogenous appearence.

Giant mature adrenal cystic teratoma in an infant

CONFLICT OF INTEREST: NONE DECLARED

Primary renal teratoma: a rare entity

Teratomas are neoplasms that arise from pluripotent cells and can differentiate along one or more embryonic germ lines. Renal teratoma is an exceedingly rare condition. Teratomas commonly arise in the gonads, sacrococcygeal region, pineal gland, and retroperitoneum. They present mainly as an abdominal mass with few other symptoms. Majority of the tumors are benign, situated on the left side and para renal, occasional lesions are bilateral. If diagnosed early, they are amenable to curative excision.Renal teratomas are rare and most have been dismissed as cases of teratoid nephroblastomas or retroperitoneal teratomas secondarily invading the kidney. The differentiation between these two neoplasms in the kidney is often problematic.We present a case of intrarenal immature teratoma in a six-month-old baby girl.

VIRTUAL SLIDES

The virtual slides for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1746249869599954.

Fetal MRI: is it really helpful?

OBJECTIVE

The aim of this study is to emphasize on the diagnostic effectiveness of fetal MRI that led to increased utilization in fetal medicine as well as its value in prognosis and decision making in the modern obstetric practice.

METHODS

One hundred five (n = 105) pregnant women were referred for a fetal MRI examination after a high detailed ultrasound examination revealed a fetal abnormality. Fetal MRI was performed using 1, 5 Tesla units, with T1, T2-weighted and diffusion-weighted images. The findings were analyzed in comparison to the previous ultrasound findings, according to the fetal organ affected and the value of the MRI for therapeutic decision making was addressed. A statistical analysis was performed.

RESULTS

The fetal MRI provides a more accurate diagnosis compared to ultrasound examination, and when the ultrasound detects fetal anomalies, the MRI can efficiently either confirm or reject the finding, proving its high value for prenatal diagnosis and perinatal and management. The sensitivity, specificity and positive predictive value of fetal MRI as a screening tool approaches 100%.

CONCLUSIONS

Despite the fact that ultrasound is the method of choice for fetal screening, MRI can add up significantly to the diagnosis and management of congenital abnormalities and the indications for MRI continue to increase as new sequences and shorter acquisition times evolve.

[Management of antenatal fetal abdominal tumors. Clues for the diagnosis of a congenital mesoblastic nephroma]

The prenatal diagnosis of abdominal mass poses the problem of its origin. Renal tumors are rarer than neuroblastoma but they are most often congenital mesoblastic nephroma. The congenital mesoblastic nephroma has a good forecast in spite of a sonographic impressive aspect. MRI can help to locate tumor but cannot tell difference between the different kinds of renal tumor. Prenatal forecast is especially linked with hydramnios and hydrops fetalis. Histolological study of the tumor is important for the prognosis. Two morphological subtypes are currently distinguished: the classic type with a good forecast and the atypical or cellular type. Distant metastases have been related only to the cellular form but especially in infants aged more than 3 months and never in the newborns. The diagnosis of the tumor does not change the mode of delivery except in case of an important volume. Complications are searched during the first days of life: hypertension, hypercalcemia, vomiting, hyperreninemia. Radical nephrectomy is performed after the end of the first week. In case of a classic form, the healing is always obtained. In case of cellular form, distant metastases are searched. In any rate, the follow-up is recommended until the end of the growth.

Congenital Mesoblastic Nephroma

Congenital mesoblastic nephroma is a rare renal tumor of early infancy with a favorable outcome after complete surgical removal. It consists of a heterogeneous group of spindle cell tumors. Early and accurate prenatal diagnosis of the renal tumor may improve the outcome of affected pregnancies by implementing the best strategy for prenatal management and delivery. But detection of congenital mesoblastic nephroma in a fetus is rare. To the authors' knowledge, there are fewer than 30 reports of a prenatal diagnosis of a mesoblastic nephroma in the literature. This case describes the prenatal sonographic diagnosis of cellular congenital mesoblastic nephroma.

Fetal and neonatal renal tumors

This is a review of renal tumors diagnosed between 1960 and 2007 in 47 fetuses and 163 infants less than 2 months old. There were 139 congenital mesoblastic nephromas, 41 Wilms' tumors, 23 rhabdoid tumors of the kidney, and 7 clear cell sarcomas of the kidney. The initial clinical manifestations, staging, management, and outcome of these patents are summarized in the tables and text.

Part I: Primary malignant non-Wilms' renal tumours in children

Non-Wilms' tumours form a small heterogeneous group of clinically significant renal malignancies in children, including renal-cell carcinoma, clear-cell sarcoma, (congenital) mesoblastic nephroma, rhabdoid tumour, and renal medullary carcinoma. Good progress has been made in the assessment of these tumours, which has led to a greater understanding of the molecular changes that occur in their development. This review is the first of two parts, and provides an updated review of the clinical presentation, imaging, and pathology of these tumours.

Mesoblastic nephroma: a case report of prenatal detection by MR imaging

We report a case of mesoblastic nephroma detected prenatally by magnetic resonance (MR) imaging. MR imaging could provide valuable information about the origin and nature of a fetal abdominal mass and help define the relationship of the mass to adjacent structures.

Atypical congenital mesoblastic nephroma presenting in the perinatal period

Congenital mesoblastic nephroma (CMN) is a rare tumour of infancy having an overall good prognosis. The less common, atypical CMNs have cellular elements in them and tend to have an unpredictable course. Occurrence in the perinatal period may further change the outcome. By reporting three patients presenting in the perinatal period with atypical CMN, an attempt is made in this paper to characterize the clinical behaviour of these variant tumours. Though one of our patients had an uneventful course, the other two had several complications including polyhydramnios, prematurity, hypertension, haemodynamic instability and tumour spillage. The course was complicated by recurrence in the latter two and refractoriness to chemotherapy and death in one. That the atypical subset of CMNs occurring in the perinatal period can have a stormy course is well illustrated by this report. Possible prognostic factors are evaluated and the sparse reports of similar cases in the literature are reviewed and compared.

Liver, meconium, haemorrhage: the value of T1-weighted images in fetal MRI

BACKGROUND

Ultrafast T2-weighted (T2-W) MRI sequences are currently considered a routine technique for fetal MR imaging. Limited experience exists with fetal T1-weighted (T1-W) imaging techniques.

OBJECTIVE

To determine MRI patterns of some fetal abdominal or haemorrhagic disorders with particular respect to the diagnostic value of T1-W images.

MATERIALS AND METHODS

In addition to standard T2-W single-shot sequences, T1-W single-shot and/or multislice sequences were employed in 25 MR examinations performed in 23 fetuses between 20 and 36 weeks of gestation for more detailed assessment of liver, meconium-filled digestive tract, haemorrhage, or further characterization of a fetal abdominal mass. Diagnostic value and presence of motion artefacts on T1-W images was recorded in each case.

RESULTS

T1-W images enabled superior delineation of fetal liver and large intestine. They provided additional diagnostic information in 9 (39%) of 23 fetuses. One false-positive and one false-negative MRI diagnosis of malrotation anomaly were encountered. Use of single-shot T1-W sequences reduced the occurrence of motion artefacts in 64%.

CONCLUSION

Our results suggest that the specific signal properties of methaemoglobin, meconium and liver are sufficiently important for T1-W sequences to become a routine part of fetal MRI protocols when dealing with digestive tract anomalies, diaphragmatic and abdominal wall defects, intraabdominal masses, and fetal haemorrhage.

Congenital intrarenal teratoma arising from a horseshoe kidney

We report a case of intrarenal teratoma arising from a horseshoe kidney. A 6-day-old girl was admitted with an abdominal mass that had been noticed at 37 weeks gestation by routine ultrasonography. At 20 days of age, a tumorectomy with a right nephrectomy was performed. The pathological diagnosis was an immature teratoma. An intrarenal teratoma is extremely rare. In addition, we believe that this case represents the first case of an immature teratoma occurring in a horseshoe kidney. The diagnosis in this type of case is difficult, but we recommend that such tumors be included in the differential diagnosis.

Prenatal diagnosis of fetal bilateral adrenal carcinoma

Fetal malignancies that are capable of metastasizing to other fetal organs and the placenta are exceedingly rare. Fetal tumors are suspected on ultrasonography in the presence of structures of abnormal shape or size that are occasionally associated with polyhydramnios and hydrops. Most of the large abdominal masses detected antenatally are renal in origin, although adrenal tumors should also be kept in mind in their differential diagnosis. We report a case of a large-for-gestational-age fetus with abdominal distention secondary to bilateral adrenal carcinoma, polyhydramnios and placental enlargement. Postmortem histological findings included nesidioblastosis, (i.e. hyperplasia of the cells of the islets of Langerhans) and adrenocortical cytomegaly, suggestive of a form of Beckwith-Wiedemann syndrome.

Renal magnetic resonance imaging

PURPOSE OF REVIEW

Current magnetic resonance imaging systems allow the visualization of normal and diseased kidney, with exquisite resolution of renal structures. Dynamic contrast magnetic resonance imaging has the potential, unique among all noninvasive modalities, to differentiate diseases that affect different portions of the vascular-nephron system. This article reviews the most important recently published studies in selected topics chosen because of their clinical relevance or potential for technical developments.

RECENT FINDINGS

Magnetic resonance imaging is used increasingly to evaluate renal masses, the prenatal genitourinary system, urinary obstruction and infection, renal vasculature, and the kidneys of transplant donors and recipients. Dynamic contrast magnetic resonance renography based on gadolinium chelated to diethylenetriamine pentaacetic acid, a safe (non-nephrotoxic) paramagnetic agent, emerges as the functional renal imaging modality of choice. Both perfusion and filtration rates can be assessed in individual kidney.

SUMMARY

Magnetic resonance imaging has the potential to provide a complete anatomic, physiologic, kidney-specific evaluation. With future advances in automated image analysis methods we can expect functional renal magnetic resonance imaging to play an influential role in management of renal disease.