嗜酸性腎臟腫瘤伴巨觀囊性變化之案例報告

張乃文¹、楊旻鑫^1,2

¹中山醫學大學附設醫院 泌尿科， ²醫學研究所

Renal oncocytic tumor with cystic change: a case report

Nai-Wen Chang¹, Min-Hsin Yang^1,2

Department of Urology¹, and Institute of Medicine², Chung Shan Medical University Hospital, Taichung, Taiwan

Introduction: We presented a case of renal oncocytic tumor with the unusual gross appearance of a cystic tumor.

Case presentation: A 74-year-old male had history of prostate adenocarcinoma, pT2 s/p robotic assisted radical prostatectomy, hypertension and type 2 diabetes mellitus. A huge left renal cyst, 9.5 cm was noted by sonography first. Abdominal CT showed well-defined cystic lesion at left perirenal space with focal connecting to renal cortex, suspect renal cyst, Bosniak II. After discussion about treatment, the patient asked for surgical intervention with laparoscopic unroofing. Surgical finding revealed a middle pole renal cyst with 350 ml dark-brownish fluid. The pathology reported oncocytic tumor with cytic change, an uncertain answer to the tumor.

Discussion: Oncocytic renal tumor is a group of morphologically and biologically heterogeneous tumor with overlapping features. However, there is still a subset of renal oncocytic tumors that do not fit into any of the current categories. The atypical IHC stains of CK7(positive, diffuse and strong) and c-kit (positive, partial), however, are not fully consistent with the typical profile described in the literature. We consulted for expertise opinion, and they considered the differential diagnoses including oncocytoma, eosinophilic chromophobe renal cell carcinoma, eosinophilic vacuolated tumor, and low-grade oncocytic tumor. Because it is difficult to assign this tumor into a documented entity in the current WHO Classification, they would suggest the generic diagnostic term "oncocytic tumor NOS".

Conclusion: More studies are needed to fully disclose the unique potential of oncocytic tumor with cystic change. Long-term clinical follow-up is recommended due to the uncertain malignant potential of this tumor.