Primary Ewing’s sarcoma of the kidney: description of two rare clinical cases and review of world literature

Ewing’s sarcoma (ES) of the kidney is an extremely rare malignant tumor characterized by an aggressive course, and therefore the disease has an unfavorable prognosis. Due to the rare occurrence, standards for the treatment of ES of the kidney have not been developed; an integrated approach is often used in therapy. In this article, we present a description of two clinical cases of kidney damage with ES in patients aged 10 and 16 who were treated at the Research Institute of Pediatric Oncology and Hematology named after Academician of the Russian Academy of Medical Sciences L.A. Durnov at N.N. Blokhin National Medical Research Center of Oncology, Ministry of Health of Russia. In the first case, there was a metastatic lesion of the kidney with the localization of the primary focus in the pelvic bones, in the second, primary ES of the kidney was diagnosed. Both patients had stage IVb at the time of diagnosis (TNM classification American Joint Commission on Cancer). In both patients, after induction chemotherapy, a complete therapeutic response (complete therapeutic pathomorphosis) was obtained. In an integrated approach, in addition to standard chemotherapy, surgery and radiation therapy, in both cases, high-dose chemotherapy with autologous peripheral stem cell transplantation was used, which made it possible to create favorable conditions for long-term remission in one of the patients, even despite the initial prevalence of the process.