罕見之腎臟旁平滑肌腫瘤：一個追蹤4年發現腫瘤擴大並接受機器人手臂腫瘤切除之個案報告

徐英傑¹、吳振宇^1、2、吳俊賢^1、2、林嘉祥^1、2

¹義大醫療財團法人義大醫院 泌尿科；

²義守大學 醫學系

A Rare Perirenal Smooth Muscle Tumor with Uncertain Malignant Potential: Case Report of a 4-Year Growth and Robotic Resection

Ying-Jie Hsu¹, Richard C. Wu^1,2, Chun-Hsien Wu^1,2, Victor C. Lin^1,2

Department of Urology¹, E-Da Hospital, Kaohsiung, Taiwan;

School of Medicine, College of Medicine², I-Shou University, Kaohsiung, Taiwan

Introduction

Smooth muscle tumors of uncertain malignant potential (STUMP) are rare and diagnostically challenging neoplasms that often occur in the uterus but can also present in extra-uterine locations, where they are even less common. STUMPs are difficult to classify definitively as benign or malignant, and their unpredictable behavior complicates management, especially as treatment guidelines are limited. Here, we report a rare case of perirenal STUMP in a female patient with congenital uterine agenesis, with a detailed follow-up over four years.

Case Report

A 41-year-old female with a history of uterine agenesis and polycystic ovarian syndrome initially presented with bilateral flank pain. Imaging revealed a 3.8 cm, non-enhancing, well-defined mass in the perirenal region. Surveillance imaging over four years demonstrated progressive growth to 6.6 cm, raising concerns of malignancy and prompting surgical intervention. (Fig A-D) The patient underwent robotic-assisted transperitoneal resection. Intraoperatively, the tumor was found to be well-encapsulated and adjacent to the upper pole of the left kidney, allowing for precise excision with minimal blood loss. The procedure was completed without complications, and histopathology confirmed a diagnosis of STUMP. Given the tumor’s unpredictable potential, long-term follow-up was recommended.

Conclusion

This case illustrates the importance of surveillance imaging in managing STUMPs, especially in rare extra-uterine presentations. Robotic-assisted resection proved an effective, minimally invasive treatment option, offering precision with favorable outcomes. Due to the potential for recurrence or metastasis, careful long-term monitoring remains essential in such cases. This report contributes to the limited literature on extra-uterine STUMP and underscores the need for individualized management strategies.