Multilocular cystic renal neoplasm of low malignant potential: experience of N.N. Lopatkin Scientific Research Institute of Urology and Interventional Radiology

Abstract

Introduction. Multilocular cystic renal cell neoplasm of low malignant potential (MCRCNLMP) or multilocular cystic renal cell carcinoma (MCRCC) is classified as a distinct nosological unit. Currently, in literature there are no results of studies based on a large number of observations. Objectives: to systemize clinical and pathomorphological characteristics of MCRCNLMP. Materials and methods . In the period from January 2011 to December 2015 in the clinic of the N.N. Lopatkin Scientific Research Institute of Urology and Interventional Radiology, 32 cases of MCRCNLMP were diagnosed among 588 patients. We have studied clinical and morphological characteristics of this disease, surgical approaches to its treatment, and long-term results, which we present in this article. Results. MCRCNLMP comprised 5.44 % of all histological cases of RCC. The majority (75 %) of patients didn’t have clinical manifestations of the disease. Т1а tumor stage corresponded to 65.6 % of tumors, Т1b stage to 28.1 %, and Т2 stage only to 6.2 %. In all cases neoplasm was characterized by moderate and mild differentiation (G1–2) per the grading system of the International Society of Urological Pathology (ISUP). Only 25 % of patients had normal body mass index. In 31 of 32 patients, long-term outcomes were observed. Median follow-up duration was 29 (14–66) months. Progression of the disease wasn’t observed in any of the patients. Conclusion. Patients with MCRCNLMP have the best oncological prognosis among patients with RCC. The necessity of classification of this tumor in accordance with the TNM system is currently dubious. Only organ-preserving surgeries should be used in treatment of the disease. For cases of MCRCNLMP, it is recommended to increase periods of control examinations proposed for patients with RCC, and diagnostic manipulations should be minimal.