低度惡性潛能多房囊性腎臟腫瘤 — 罕見病例報告與文獻回顧

郭炫廷、楊景偉、黃家倫、謝啟誠、王曉暹、陳光國、張心湜 與 蔡昇翰

振興醫療財團法人振興醫院泌尿部

Multilocular cystic Renal Neoplasm of Low Malignant Potential - A Rare Case Report and Literature Review

Hsuan-Ting Kuo, Chin-Wei Yang, Chia-Lun Huang, Chi-Cheng Hsieh, Hsiao-Hsian Wang, Kuang-Kuo Chen, Luke S. Chang, and Sheng-Han Tsai

Department of Urology, Cheng Hsin General Hospital, Taipei, Taiwan

Introduction: Multilocular cystic Renal Neoplasm of Low Malignant Potential (MCRNLMP) accounts for less than 1% of all renal tumors. Despite most of the patients diagnosed with MCRNLMP have favorable clinical prognosis, we can hardly differentiate MCRNLMP from renal cell carcinoma (RCC) according to pre-operative image. We herein presented a case diagnosed with MCRNLMP.

Presentation of case: A 56-year-old man was incidentally found to have a right renal lesion at outside hospital. Abdominal CT scan was arranged and showed cystic mass at lower pole of right kidney. The cystic lesion is septated with measurable enhancement and is reported as Bosniak class III by radiologist. Whole body bone scan revealed no evidence of bony metastasis. He came to our urology outpatient clinic for second opinion. Because of the possibility of malignancy including cystic RCC, we suggested surgical removal of the tumor and the patient agreed. Right robotic-assisted partial nephrectomy was performed. The pathology turned out to be MCRNLMP. He was under regular follow up at our urology outpatient clinic without recurrence.

Discussion: MCRNLMP was termed as multilocular cystic RCC and categorized as a rare subtype of clear cell RCC before. It was, however, redefined in 2016 WHO classification because it has excellent outcomes, and the chance of recurrence or distant metastasis is rare. While most of patient with MCRNLMP was discovered incidentally by sonography, contrast CT scan is still the gold standard for evaluation of cystic lesion of kidney. A great majority of MCRNLMP lesions were reported as Bosniak class II, IIF and III, and the chance of malignancy is 6%, 6.7% and 55.15 respectively. Surgical removal of the tumor is usually suggested to rule out RCC. Despite technically challenging, nephron-sparing surgery with laparoscopic or robotic approach is always recommended when clinically applicable compared with radical nephrectomy to preserve renal function as much as possible because of the negligible risks of disease progression.