"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.

Primary intracranial smooth muscle tumor associated with Epstein-Barr virus in immunosuppressed children: two cases report and review of literature.

Primary intracranial smooth muscle tumors are rare. Most cases are related to Epstein-Barr virus proliferation in immunocompromised patients such as organ solid recipients. Only a few cases have been reported in pediatric patients. The clinical features are very variable depending mainly on the location and size of the smooth muscle tumor (SMT) and the pathogenesis is poorly understood. We describe two cases of intracranial SMT localized in the temporal lobe and associated with EBV in immunosuppressed children. A review of the literature associated with intracranial leiomyomas was also done.

Laryngeal Epstein-Barr Virus-Associated Smooth Muscle Tumor in an Undernourished Child.

Smooth muscle tumors associated with Epstein-Barr virus infections (EBV-SMT) of laryngeal origin are exceedingly rare and have been reported in few adult patients, but not in children. This reported case describes a lesion found in the larynx of an 8-year-old Guatemalan undernourished girl. Microscopically, the lesion showed a highly cellular mesenchymal spindle cell tumor, containing frequent lymphocytes. The immunohistochemical analysis revealed positivity for α-smooth muscle actin and h-caldesmon. In addition, most of the tumor cells were positive for EBV by in situ hybridization. To the best of the author's knowledge, this is the first literature-reported case of laryngeal EBV-SMT occurring in an undernourished child.