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We present an unusual renal developmental disorder in a female infant and male sibling born in a subsequent pregnancy. Both children had prenatally diagnosed bilateral nephromegaly and survived for 6 and 10 days after birth, respectively. Both infants demonstrated the presence of bilaterally large cerebriform kidneys with numerous small lobulations containing immature glomeruli admixed with primarily intralobar nephrogenic rests without Wilms tumor. The pathology was most consistent with universal nephroblastomatosis with nephromegaly, a rare entity described in only 4 cases and in only 1 of these as a possible inherited disorder.

We report a 1-year 11-month-old girl demonstrating a large renal mass with a unique presentation on imaging (US, CT and plain radiography), pathology and histology. The imaging features did not correspond with a Wilms' tumour, the most commonly found renal tumour in the child of this age. The US and CT findings resembled a benign lesion with an unusually high fat content. Histological evaluation demonstrated a congenital mesoblastic nephroma, a tumour entity typical for the neonatal period or early infancy, with an additional unusual, predominantly lipomatous differentiation.

We report on 2 patients with congenital malignant rhabdoid tumor, one located to the kidney and the other to the soft parts of the cheek. Initial diagnosis was performed through percutaneous fine-needle aspiration biopsies, which yielded cytologic smears exhibiting highly characteristic rhabdoid cells, i.e., cells with a large, vesicular nucleus with a prominent nucleolus and cytoplasm exhibiting a large, dense, paranuclear inclusion. Interphase FISH demonstrated only one signal (heterozygous deletion) for the BCR gene in both cases, supporting the diagnosis. Surgical pathology and immunohistochemistry of both cases confirmed the diagnosis. Both patients died within the following 6 mo to 1 yr., (Copyright 2002 Wiley-Liss, Inc.)

Purpose: Horseshoe kidneys are the most common renal fusion anomalies. Ureteropelvic junction obstruction, urolithiasis and renal malignancies are the most common complications that occur in this patient population. Endourological management of these complications has decreased perioperative morbidity. We identified the applications of minimally invasive surgery for treating complications secondary to horseshoe kidney., Materials and Methods: A comprehensive literature review of the different endourological approaches in the management of complications secondary to horseshoe kidney was performed using MEDLINE., Results: Ureteropelvic junction obstruction can be managed by percutaneous endopyelotomy or laparoscopic pyeloplasty with good results. Small stones associated with horseshoe kidney are best managed by shock wave lithotripsy, while stones that have failed management by shock wave lithotripsy or are greater than 2 cm. are best managed percutaneously. All patients should undergo metabolic evaluation. Ureteroscopy or shock wave lithotripsy is associated with a higher residual stone rate than the percutaneous approach. Laparoscopic nephrectomy is a safe and feasible option for benign and malignant horseshoe kidney diseases., Conclusions: Endourological techniques can be safe and effective for treating complications secondary to horseshoe kidney.

A preterm boy was born at 34 weeks. Prenatal ultrasonography showed oligohydramnios, fetal ascites, large kidneys, and small thorax. He died 21 h after birth of respiratory insufficiency. Autopsy revealed Potter's-like facies, hypoplastic lungs, ascites, and bilateral nephromegaly (renal weight almost 10 times normal). The kidneys were finely nodular externally, solid, and cerebriform on cut section. Histologically, they showed a diffusely distorted architecture of jumbled lobules, hyperplasia of cortical-type tissue with inconspicuous proximal tubules, relative hypoplasia of medullary tissue, tubulointerstitial dysplasia, and perilobar nephrogenic rests. The renal features represent a variety of the universal or panlobar (also called pancortical or infantile) type of nephroblastomatosis. To our knowledge, this is only the third such case reported. In the brain, each lateral ventricle contained a yellow gelatinous mass. Histologically, the masses consisted of a pseudomyxoid matrix with delicate fibers and focal adipocyte clusters, all confined within choroid plexus. We consider these lesions fibrolipomatous hamartomas.

A unilateral cystic renal process discovered prenatally was removed in a neonate. Dysplastic cysts were associated with diffuse (both intra- and perilobar) nephroblastomatosis. We describe a comprehensive immunohistological study confirming the transition observed on simple histology between the different structures: nephrogenic rests (CD9+, CD24+/-, CD56+/-), glomeruloid bodies (CD10++, CD35++), ducts lined by columnar epithelium (CD9+, CD24+, CD56++), cysts lined by cuboidal or thin epithelium (some cells CD10+, CD26+, others EMA+, CD24+). Although no typical S-shaped bodies are seen, small cysts and ducts with a columnar epithelium are considered similar. The dysplastic primitive ducts are KL1++, vimentin+/-, CD9+, CD24+. With a view to assessing dysplastic preneoplastic potential, the value of CD56 and Ki67 as activation antigens with possible prognostic significance is discussed.

Congenital mesoblastic nephroma (CMN) is a rare tumour arising in early infancy. This is the first reported case of CMN arising in a solitary kidney. The literature and radiological features of CMN are reviewed.

The occurrence of nodular renal blastema and renal dysplasia was determined in a retrospective study of 75 cases of congenital obstructive uropathy. Nodular renal blastema was present in 3 upper pole nephrectomy specimens removed as a consequence of nonfunction owing to ectopic ureterocele; none was dysplastic. A more differentiated type of nodular renal blastema was present in 3 other total nephrectomy specimens, bilateral involvement in a case of posterior urethral valves and unilateral nodular renal blastema associated with ureteral atresia. This subset of differentiated nodular renal blastema was associated with renal dysplasia.

A newborn male presented with bilateral nephromegaly and mild hypertension. Function of the right kidney was reduced on excretory urography. Ultrasound showed bilaterally enlarged kidneys with increased echogenicity and poorly defined corticomedullary junctions. Areas of decreased medullary enhancement were seen on CT. Renal biopsy demonstrated lymphangioma, probably arising from the peripelvic renal tissues.

We believe this to be the third reported case of an unusual congenital sacral tumor-like lesion characterized histologically by the presence of dysplastic and immature renal-like tissue with a predominant glomerular and tubular structure. This lesion appears important in the differential diagnosis of extrarenal nephroblastoma, and should be regarded as a dysplastic overgrowth. An origin from mesonephric or metanephric remnants is suggested.

Congenital anomalies of the urinary tract are of great pathological importance and account for about 10,9 per cent of all fetal and neonatal autopsies. This paper reports 17 cases of such lesions compiled from 156 consecutive autopsies of newborn infants performed during 33 months at C.H.R. de Bordeaux (France). Each malformation is discussed, using embryological classification. These lesions can occur independently but usually they are associated with other organ abnormalities. Whenever, an hereditary syndrome must be seek after. In a first part, we present the anomalies of the kidney proper. In a second part, we shall present the anomalies of the excretory apparatus, bladder and urethra.