Congenital cystic mesoblastic nephroma

Review of paraneoplastic syndromes in children

Paraneoplastic syndromes are defined as clinical syndromes that are not related to direct tumor invasion or compression but are secondary to tumor secretion of functional peptides/hormones or related to immune cross-reactivity with normal host tissue. Paraneoplastic syndromes have a wide range of presentations and can present before the primary malignancy or tumor recurrence is diagnosed. They can mimic non-neoplastic processes, making detection, diagnosis and treatment difficult. However, they can also provide clues to the presence of an underlying malignancy. In this paper, we reviewed a range of paraneoplastic syndromes that can occur in children including: (1) neurologic (opsoclonus-myoclonus, limbic, anti-N-methyl-d-aspartate [NMDA] and anti-Ma2 encephalitis and myasthenia gravis); (2) endocrine (neuroendocrine tumors, hypercalcemia, SIADH [syndrome of inappropriate antidiuretic hormone secretion], osteomalacia/rickets and ROHHAD [rapid onset of obesity, hypoventilation, hypothalamic dysfunction and autonomic dysregulation]); and (3) dermatologic/rheumatologic syndromes (hypertrophic osteoarthropathy and paraneoplastic pemphigus). Familiarity with these syndromes can aid in early diagnosis, treatment and imaging optimization.

Congenital Giant Dysplastic Kidney Presenting as Respiratory Distress: A Case Report

Multicystic dysplastic kidney (MCDK) is the most common form of renal cystic disease in children and is one of the most common causes of abdominal mass in infancy. Here in we are reporting a rare case of a large MCKD that caused respiratory compromise and the infant presented with respiratory distress.

A case of fetal congenital mesoblastic nephroma with oligohydramnios

Although congenital renal tumors are rare, congenital mesoblastic nephroma (CMN) is the most common renal tumor in early infancy. It is non-metastatic, well differentiated, amenable to surgical removal, and carries a good prognosis. Polyhydramnios has been detected in most of the published cases of CMN. However, we experienced a rare case of fetal CMN associated with oligohydramnios. A 28-yr old woman at 34 weeks of gestation was referred to our hospital for oligohydramnios and a fetal abdominal mass. An ultrasonography revealed a huge, well-encapsulated mass arising from the right kidney. An emergency cesarean section was performed due to fetal distress. After birth, despite intensive neonatal care, the baby died because of renal failure, disseminated intravascular coagulopathy, pulmonary edema, together with other problems.

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.

Genitourinary imaging techniques

In the current era of pediatric uroradiology, use of nuclear medicine, ultrasonography, CT, and MRI has been valuable in the identification and management of genitourinary diseases. Excellent information about the renal parenchyma and renal function is currently attainable with current cross-sectional imaging techniques that can identify tissue differentiation of lesions, distinguish dilatation of the pelvocalyceal system, and determine margins of the kidney and perirenal space. Invasive angiography is limited in application specifically to vascular diseases, although they are uncommon in childhood. Because of these newer techniques, intravenous urography has lost its position as the "cornerstone" of urinary tract imaging and is used mainly to identify pathologic conditions of the ureters.

Gene expression profiling of mesoblastic nephroma and Wilms tumors—comparison and clinical implications

OBJECTIVES

To better understand the molecular mechanisms in the tumorigenesis and progression of mesoblastic nephroma (MN), we studied its gene expression profiles. MN is the most common tumor of the neonatal kidney. It occurs in a younger age group than the Wilms tumor (WT). To date, very little is known about the etiology and pathogenesis of MN.

METHODS

Using microarrays containing 22,943 cDNA, we analyzed the expression profiles of MN and compared its expression profiles with those of several other types of kidney tumors, including WT.

RESULTS

MN has a distinct molecular signature that clusters close to the WT, suggesting that both types of tumor share some similarity in gene expression and biology. When comparing the two profiles closely, we identified a number of genes that are commonly upregulated in both tumors, including insulin-like growth factor 2, thrombospondin 4, and mesenchyme homeo box 1. We also identified a set of genes that distinguish MN from WT, some of which may underlie the difference in their behaviors and can be used as diagnostic markers. Among this group of genes, topoisomerase II-alpha, highly expressed in WTs, is not overexpressed in MN. Immunohistochemical staining of topoisomerase II-alpha in additional cases of WTs and MNs confirmed this distinction further.

CONCLUSIONS

The results of our study demonstrated that MN has a distinct gene expression profile and that some of the newly identified genes can be potentially used as novel diagnostic markers.

Unilateral multicystic dysplastic kidney: experience in children

OBJECTIVES

To report a retrospective study of unilateral multicystic dysplastic kidneys (MCDK) in children, assessing the contralateral kidneys and urinary tract, the functional consequences, and the urological and nephrological management and outcome, as unilateral MCDK is the most common cause of renal cystic disease in children, and malformations of the contralateral urinary tract and kidney (pelvi-ureteric obstruction, megaureter, reflux, renal dysplasia) have been reported.

PATIENTS AND METHODS

The study included 97 patients (60 boys, 37 girls) with MCDK seen between 1985 and 1998; 82 were diagnosed in utero by ultrasonography (US). After birth, the diagnosis was verified by US, renal scanning (in 93) or intravenous urography (in four), and 89 (92%) had voiding cysto-urethrography (VCUG). Of the 97 children, 87 (90% had a mean (range) follow-up of 44.3 (15-115) months.

RESULTS

The MCDK was removed in 17 children; the follow-up of 75 children (five lost to follow-up) showed total involution of the MCDK in 25%, shrinkage in 60% and a stable size in 15%. None had any sign of malignancy. The contralateral kidney showed anomalies in 19 of 97 children (20%); 12 had a dilated renal pelvis (two with megaureter), six had a high echogenicity of the contralateral kidney (one had reflux, and two also pelvic dilatation). In only four of the 89 children was reflux found by VCUG; 16 of the 19 anomalies were detected by US. Five children needed surgery on the contralateral urinary tract (three a pyeloplasty, and one each a pyeloplasty plus ureteroneocystostomy, and an antireflux procedure). Of the contralateral kidneys 43% showed compensatory hypertrophy. There was mild renal insufficiency in three children; renal function seemed to be slightly impaired in many. Five infants had hypertension (four with spontaneous resolution) caused by renal scarring after pyelonephritis or inborn dysplasia of the contralateral kidney. There were symptomatic urinary tract infections in seven children.

CONCLUSION

US can be used safely to diagnose unilateral MCDKs and malformations of the contralateral urinary tract and kidney. In cases where US of the dysplastic kidney remains uncertain renal scintigraphy is necessary to detect the lack of renal function. The low rate of reflux makes routine VCUG unnecessary if the contralateral upper urinary tract and kidney appear to be normal on US. Nephrectomy of the dysplastic kidney in typical cases is also unnecessary. A long-term nephro-urological follow-up of children with MCDK is recommended.

[Malignant renal tumors before one year of age. Experience of a North African pediatric surgery service]

The malignant tumours of the kidney are not very frequent during the first year of life and pose diagnostic and therapeutic problems. The aim of this work is to make an analysis of the epidemiologic, clinical and anatomo-pathological characteristics of these tumours during the first year of life and a development on the therapeutic methods and their results.

MATERIAL AND METHODS

[corrected] This is a retrospective study of 8 observations of malignant tumours of the kidney whose first symptomatology appeared during the first year of life.

RESULTS

The malignant tumours of the kidney observed before the one year age constituted 18% of the tumours of the kidney in the child. A female prevalence was noted with a sex-ratio of 0.6. The assessment of extension found cutaneous (one case), ganglionic (one case) and pulmonary (two cases) metastases. First chemotherapy was prescribed to five patients. The surgery consisted on a widened nephrectomy in seven cases and a tumorectomy for an infant presenting a nephroblastomatosis. The tumour corresponded to a nephroblastoma in seven cases and a rhabdoide tumour in the last case. Mortality was high (50%) caused by the toxicity of chemotherapy in three cases and an advanced stage of cancer in one case.

CONCLUSION

Renal tumoral pathology occurring in infants less than one year of age poses true etiologic and therapeutic problems. The high frequency of the nephroblastoma and the absence of benign tumour in our series encourage us to evocate more often the malignant renal tumours and to practice per cutaneous biopsies in case of diagnostic doubt.

Multicystic congenital mesoblastic nephroma

This report describes an unusual example of congenital mesoblastic nephroma cellular variant that presented in a 1-week-old neonate as a multicystic tumor of the kidney. Extensive pseudocystic cavitation resulted from progressive accumulation of ground substance in a loosely myxoid tissue composed of stellate- and spindle-shaped cells that compressed and infiltrated renal tissue. The cells of the tumor were positive for vimentin and smooth muscle actin. The patient is alive and well 16 years after surgery. Differential diagnosis from segmental cystic dysplasia, cystic intralobar nephrogenic rest, cystic nephroma, cystic partially differentiated nephroblastoma, cystic nephroblastoma, and cystic clear cell sarcoma of the kidney, all of which may present at this age, is discussed.