Cystic renal disease and tuberous sclerosis in infants

Renal cystic diseases in children: new concepts

This review highlights the changes that have occurred in the general approach to cystic renal diseases in children. For instance, genetic mutations at the level of the primary cilia are considered as the origin of many renal cystic diseases. Furthermore, these diseases are now included in the spectrum of the hepato-renal fibrocystic diseases. Imaging plays an important role as it helps to detect and characterize many of the cystic diseases based on a detailed sonographic analysis. The diagnosis can be achieved during fetal life or after birth. Hyperechoic kidneys and/or renal cysts are the main sonographic signs leading to such diagnosis. US is able to differentiate between recessive and dominant polycystic kidney diseases, hepatocyte nuclear factor 1 Beta mutation, glomerulocystic kidneys and nephronophtisis. MR imaging can, in selected cases, provide additional information including the progressive associated hepatic changes.

[Renal manifestations in tuberous sclerosis]

BACKGROUND

Tuberous sclerosis is a rare inherited disease which can involve several organs. Renal involvement is one of the most severe manifestations of the disease. We analysed in this study renal involvement of tuberous sclerosis.

METHODS

We studied retrospectively nine cases of tuberous sclerosis with renal involvement diagnosed between 1994 and 2005. The diagnosis was based on the presence of typical extra-renal manifestations and familial history of tuberous sclerosis.

RESULTS

There were eight females and one male. Their mean age was 40.8+/-16.4 years (range: 15-62). At first presentation, we noted hypertension in three cases, proteinuria in seven cases, hematuria in eight cases and renal failure in five cases (end stage renal failure in four cases). By ultrasonography, we found angiomyolipoma in one case, cysts in four cases and angiomyolipoma associated to cysts in four cases. Nephrectomy was performed in two patients, in one case for hydronephrosis secondary to urolithiasis and in the other for hemorrhagic complication. In the later, pathological examination revealed renal carcinoma. At last evaluation, two patients were lost to follow-up, one had normal serum creatinine, five were on renal replacement therapy and the latter died from sepsis following kidney removal.

CONCLUSIONS

In our patients, renal disease was diagnosed late at chronic renal failure stage. Patients with end-stage renal failure require dialysis and renal transplantation, but we recommend binephrectomy after starting dialysis and before transplantation due to the risk of cancer and bleeding related to angiomyolipomas.

Isolated unilateral tuberous sclerosis-associated renal cystic disease in a neonate

We present a male infant with antenatally detected, focal, unilateral apparently isolated renal cystic disease with morphological features of renal involvement in tuberous sclerosis. Only one previous case with similar presentation has been described. Most affected children present with either diffuse bilateral renal cystic disease or extrarenal manifestations. The major genes involved in tuberous sclerosis are now well described, and early onset of severe renal cystic disease in affected children often is related to the presence of a contiguous gene deletion syndrome involving TSC2 and PKD1 on chromosome 16.

The tuberous sclerosis complex and its highly variable manifestations

PURPOSE

Tuberous sclerosis is an autosomal dominant neurocutaneous syndrome affecting multiple organ systems and demonstrating highly variable clinical manifestations. Mutations in 2 tumor suppressor genes, TSC1 and TSC2, are linked to the evolution of the hamartomatous lesions. We describe the incidence and epidemiology, variable clinical manifestations and their relationships to renal pathology, and the management of morbid sequelae.

MATERIALS AND METHODS

Using the search term tuberous sclerosis, we performed a MEDLINE search of the literature identifying 3,196 articles and selected those from urological, surgical, oncological, genetic and pediatric journals. Special focus was placed on the incidence and management of renal lesions and on different clinical manifestations and how they relate to renal tumors.

RESULTS

Due to improved identification of the variable phenotypic expression, the reported incidence has increased. TSC1 and TSC2 mutations are related to various phenotypic manifestations and risks of malignancy, such as an increased incidence of the TSC2 mutation in patients with renal cell carcinoma. Renal sparing surgery and selective embolization techniques have mitigated the morbidity of the lesions.

CONCLUSIONS

We now have a better understanding of the variability at the genotypic and phenotypic levels of the disease. We recommend that patients with tuberous sclerosis complex be evaluated by a multidisciplinary group of clinicians, including urologists, dermatologists, neurologists, pediatricians and geneticists. Close attention to these manifestations is necessary to ensure appropriate treatment of the sequelae of the tuberous sclerosis complex.