"Epstein-Barr virus associated smooth muscle tumour as an unusual cause of ureteric graft obstruction in a child".

BACKGROUND: Epstein-Barr virus (EBV) is a DNA virus with oncogenic potential, especially in immunocompromised patients. EBV can promote smooth muscle proliferation, resulting in EBV-associated smooth muscle tumors (EBV-SMT). METHODS: We report a case of a 10-year-old child with end-stage renal disease secondary to hypoplastic crossed and fused kidneys who underwent kidney transplantation. EBV serology was unknown for the donor and negative for the recipient; three months after he had a primary EBV infection. Two years after the transplantation, percutaneous nephrostomy was performed because of a drop in the estimated glomerular filtration rate and severe dilatation of the graft. Nephrography showed contrast enhancement of the pelvis of the graft kidney and proximal ureter, with a clear blockage at the level of the mid ureter and no passage towards the bladder. A 1.5-cm tumor was found causing intraluminal compression of the mid ureter. RESULTS: Complete resection of the tumor and distal ureter was performed leaving a short proximal ureter. A tension-free uretero-ureteroanastomoses was achieved using the native ureter. There were no surgical complications. Histologic evaluation showed spindle-shaped muscle cells, moderate pleomorphism, and inflammatory infiltration. Immunohistochemical staining was positive for muscle-specific actin. Epstein-Barr encoding region (EBER) in situ hybridization was positive, confirming the diagnosis of EBV-associated SMT. CONCLUSIONS: EBV-SMT is an exceedingly rare oncological entity that may develop in either the graft or any other organ. The clinical findings are location related. EBV seroconversion following transplantation might be a risk factor for the development of SMT in solid organ recipients.

BK virus associated pronounced hemorrhagic cystoureteritis after bone marrow transplantation.

Ureteral stenosis due to reactivation of the BK virus (BKV) in a state of immunodeficiency is very rare. More common is the appearance of a hemorrhagic cystitis. This report not only shows bilateral ureteral stenosis after bone marrow transplantation, but also presents severe complications as chronic pelvic pain and impaired kidney function as well as irreparable damage to the whole urinary tract leading to nephroureterectomy, subtrigonal cystectomy and orthotopic ileal neobladder. Finally renal transplantation was required. To our knowledge this is the first case in the literature where such a severe course of BKV associated hemorrhagic cystoureteritis is described.

Recurrent renal allograft dysfunction due to ureteric stenosis in a patient with the BK virus infection.

Diseases of the genitourinary tract in association with the BK virus (BKV) infection are increasing among renal allograft recipients. We herewith report a young, female renal transplant recipient who presented with allograft dysfunction secondary to proximal ureteric stenosis. The allograft function improved dramatically after correction and stenting of the stenosis. Our case suggests that screening for BKV infection should be an integral part of evaluation of allograft dysfunction.

Adenovirus-induced obstructive uropathy with acute renal failure in an immunodeficient child.

Viral infections represent severe complications in immunodeficient patients, associated with significant morbidity and mortality. We report a case of a bone marrow-transplanted adolescent with hemorrhagic cystitis 4 weeks after transplant, associated with renal failure because of obstructive pyelonephritis. Diagnostic workup finally revealed adenovirus infection. A double-J stent was inserted with spontaneous favorable evolution thereafter. Adenovirus infection in an immunocompromised patient can cause hemorrhagic cystitis without specific symptoms and might evolve toward obstructive pyelonephritis because of tubular necrosis. Diagnosis is made by urine culture and/or blood polymerase chain reaction. In case of fatal dissemination, diagnosis might only be revealed on autopsy.

Clinical characteristics of obstructive uropathy associated with rotavirus gastroenteritis in Japan.

AIMS: Rotavirus gastroenteritis is severe and often results in dehydration and pre-renal azotemia. However, we have encountered four children with acute obstructive uropathy associated with acute rotavirus gastroenteritis, and several similar cases have been reported. Therefore, the aim of the present study was to clarify the epidemiology and clinical features of acute obstructive uropathy associated with acute rotavirus gastroenteritis in Japanese children. PATIENTS AND METHODS: We sent questionnaires to all members of the Japanese Society for Nephrology and all authors who had published case reports of this disease in Japan, inquiring about patient age at diagnosis, sex, the type of stones, laboratory data and other factors. RESULTS: 21 reported patients were evaluable, ranging from 0.4 to 3 years. The sex distribution showed a strong male prevalence. Oliguria had appeared about 7 days after the onset of gastroenteritis. Most of the patients showed hyperuricemia and hyponatremia. The stones consisted mainly of ammonium acid urate. The patients were discharged with normal renal function. CONCLUSION: Although obstructive uropathy associated with rotavirus gastroenteritis is very rare, this disease condition should be explored when anuria is refractory to sufficient fluid replacement therapy or when oliguria persists despite recovery of the gastrointestinal symptoms.

Reversible ureteral obstruction due to polyomavirus infection after percutaneous nephrostomy catheter placement.

BK virus (BKV) is a human polyomavirus that remains latent in the urinary tract epithelium in most individuals. However, in immunocompromised states, including after hematopoietic stem cell transplantation (HSCT), BKV may reactivate and cause infection predominantly affecting the bladder, commonly manifested as hemorrhagic cystitis. Renal insufficiency, occasionally requiring hemodialysis, is not uncommon and was previously attributed to medications or the development of tubulointestitial nephritis. We report a series of 6 HSCT recipients who developed obstructive uropathy of the upper urinary tract system secondary to inflammation and hemorrhage involving the upper uroepithelium, causing ureteral stenosis. Temporary placement of a percutaneous nephrostomy catheter relieved the obstruction and significantly improved kidney function, successfully preventing progression to more advanced renal disease in these patients.

BK virus-associated renal problems--clinical implications.

BK virus (BKV), a human polyomavirus, infects most of the human population, but clinically relevant infections are usually limited to individuals who are immunosuppressed. After primary infection, BKV remains latent in the kidneys and can be reactivated in immune deficiency conditions, including transplantation. As primary infection occurs in childhood, BKV may be particularly important in the pediatric transplant population. BKV is associated with tubulointerstitial nephritis and ureteric stenosis in renal transplant recipients and hemorrhagic cystitis in bone marrow transplant recipients. There are increasing reports of BKV causing nephropathy and cystitis in non-renal solid organ transplant recipients and other immunodeficiency diseases. This might be related to the use of more potent immunosuppressive regimens or increasing awareness of BKV as an important pathogen. Diagnosis of BKV disease is by biopsy. Histopathological changes in renal biopsy specimens may mimic rejection or drug toxicity, but BKV nuclear inclusions can be seen. Treatment is by reduction of immunosuppression. Antiviral agents such as cidofovir are showing promise. BKV DNA polymerase chain reaction in blood or biopsy may be helpful in monitoring therapy. The impact of BKV disease in children is not well understood and prospective studies are needed to elucidate this further. This article reviews the current understanding of BKV-associated renal problems.

Four cases of CMV ureteritis: emergence of a new pattern of disease?

Although cytomegalovirus (CMV) infection is common in renal transplant recipients, urinary tract involvement has been rare. Only six cases of symptomatic ureteritis have been reported in renal transplant recipients and all within the last five years. We describe an additional four cases of CMV ureteritis. The presentation of CMV ureteritis is obstructive nephropathy often in the absence of systemic illness. Presentation may also mimic allograft rejection with minimal obstructive symptoms. We hypothesize that CMV ureteritis is an emerging complication of CMV disease, possibly due to changes in transplant practice.