Login to Access Video or Poster Abstract: MP67-19
Sources of Funding: National Natural Science Foundation of China (Grant 81172418) and Beijing Municipal Natural Science Foundation (Grant 7142160).

Introduction

Multilocular cystic clear cell renal cell neoplasm of low malignant potential or multilocular cystic renal cell carcinoma (MCRCC) is a rare distinct subtype of clear cell renal cell carcinoma (RCC). As a rare subtype of renal cell carcinoma, this disease was mostly reported in literature as small cases series, some features about this disease remains unclear, an unresolved issue is whether this disease should be staged as other types of RCCs due to its low nuclear grade and minimal tumor burden. The present study aimed to characterize the clinical and pathologic features of MCRCC.

Methods

From January 2006 to December 2014, 76 cases were identified as MCRCC among 4345 patients with RCC at our institution. Their clinical and characteristics, surgical management, pathologic features, and outcomes were retrospectively reviewed.

Results

The incidence of MCRCC in our patients with RCC was 1.7%. The mean age at diagnosis was 46.7±10.5 years (range,18 to 80 years). Most cases showed no symptoms. Nuclear grade was unrelated to the TNM stage (P=0.451). Of these 76 patients, 66 (86.8%) were followed up for a median of 52 months, and no tumor recurrence or metastasis was found, no differences were found in the prognosis of different TNM groups.

Conclusions

The incidence of MCRCC in patients with RCC is low. The nuclear grade and prognosis of MCRCC cases was unrelated to the TNM stage, suggesting that the current stage criteria might not suitable for this lesion. Patients with MCRCC have an excellent prognosis; thus, the follow-up interval after surgery can be longer to minimize unnecessary examinations.

Funding

National Natural Science Foundation of China (Grant 81172418) and Beijing Municipal Natural Science Foundation (Grant 7142160).