Progression rate in Bosniak category IIF complex renal cysts

Abstract Objective: To evaluate progression rate of Bosniak category IIF complex renal cysts and the malignancy rate among surgically resected cysts. Materials and Methods: We performed a database search for complex renal cysts classified as Bosniak category IIF on computed tomography or magnetic resonance imaging between January 2008 and April 2016. Follow-up examinations (computed tomography or magnetic resonance imaging) were used in order to evaluate progression (Bosniak category reclassification) and stability, the latter being defined as remaining stable for a minimum of six months. Pathology reports were used as the reference to assess the malignancy rate of surgically resected cysts. Results: A total of 152 cysts in 143 patients were included in the final analysis. Seven cysts (4.6%) were reclassified on follow-up studies, and mean time to progression was 20 months (range, 1 month to 4 years). Three cysts were surgically resected. All three were diagnosed as low-grade malignant renal cell carcinomas (RCCs): one clear cell RCC and two papillary RCCs. The remaining 145 cysts remained unchanged after a mean follow-up period of 28 months (range, 6 to 118 months). Conclusion: The progression rate in Bosniak category IIF cysts was low. Even lesions that were upgraded on follow-up remained stable, indicating an indolent behavior. Our data support the idea of conservative management of Bosniak IIF renal cyst.

摘要 目的：评估博斯尼亚克IIF类（Bosniak category IIF）复杂性肾囊肿的进展速率，以及手术切除囊肿的恶性发生率。材料与方法：本研究检索了2008年1月至2016年4月期间，经计算机断层扫描（computed tomography）或磁共振成像（magnetic resonance imaging）确诊为博斯尼亚克IIF类复杂性肾囊肿的病例数据库。通过随访检查（计算机断层扫描或磁共振成像）评估囊肿进展（即博斯尼亚克分类重新分级）与稳定性，其中稳定性定义为至少6个月内无变化。以病理报告作为参考标准，评估手术切除囊肿的恶性发生率。结果：最终分析共纳入143例患者的152个肾囊肿。其中7个囊肿（4.6%）在随访影像学检查中出现分级上调，进展的平均时间为20个月（范围：1个月至4年）。共3个囊肿接受手术切除，均被诊断为低度恶性肾细胞癌（renal cell carcinoma, RCC）：1例为透明细胞肾细胞癌，2例为乳头状肾细胞癌。剩余145个囊肿在平均28个月的随访期内（范围：6至118个月）未发生变化。结论：博斯尼亚克IIF类肾囊肿的进展速率较低。即便在随访中出现分级上调的病变，其病情仍保持稳定，提示该类病变具有惰性生物学行为。本研究数据支持对博斯尼亚克IIF类肾囊肿采取保守治疗方案。