Clinicopathological Characteristics and Typing of Multilocular Cystic Renal Neoplasm of Low Malignant Potential (MCRNLMP): a patients’ management report of 76 cases

Abstract Background The association between computed tomography (CT) imaging characteristics and clinical growth rate of multilocular cystic renal neoplasm of low malignant potential (MCRNLMP) have not been reported. Our study focused on the correlation of CT imaging and growth rate to investigate the distinguished characteristics in MCRNLMP versus renal cysts, and explore the optimized management. Methods Data regarding 1520 patients including 1,444 patients with renal cysts and 76 patients with MCRNLMP who underwent renal cyst decompression, radical nephrectomy, or nephron sparing surgery due to renal cystic disease between Jan 2013 and Dec 2021 in our institution were retrospectively collected and analyzed. Bosniak classification for imaging modality and the 2016 WHO criteria for clinic pathology were used for detection of MCRNLMP. Results In our study, MCRNLMP accounted for 1.48% of patients with “simple renal cysts”, 5.26% of the patients with “complex renal cysts”, and 12.11% of the patients with “renal tumors combined with renal cysts” (P < 0.001); MCRNLMP accounted for 22.37% and 0.66% of patients with cysts’ growth rate ≥ 2.0 cm/year and < 2.0 cm/year, repectively. Of 76 MCRNLMP cases, after renal cyst de-topping decompression, no recurrence or metastasis was found in 9 patients who underwent nephron-sparing surgery or radical nephrectomy again, while only 1 suspicious recurrence was found by CT of 67 patients underwent actively monitored in postoperative 3-year follow-up. Conclusions MCRNLMP can be slightly identified and divided into three types through the potential predictors of Computed tomography (CT) scanning and growth rate. For MCRNLMP, partial nephrectomy is the first choice and radical nephrectomy should be avoided as much as possible, in addition, active monitoring can also be adopted after surgery to avoid unnecessary nephrectomy.