Imaging Characteristics of Clear Cell Papillary Renal Cell Carcinoma: Identifying the Sheep in Wolf’s Clothing

Title:Imaging Characteristics of Clear Cell Papillary Renal Cell Carcinoma: Identifying the Sheep in Wolf’s Clothing

Volume: 20

Author(s): Shunfa Huang, Qiying Tang, Minrong Wu, Lianting Zhong, Danlan Lian, Yuqin Ding and Jianjun Zhou*

Affiliation:

• Department of Radiology, Zhongshan Hospital (Xiamen), Fudan University, No.668 Jinhu Road, Huli District, Xiamen 361015, China
• Department of Radiology, Zhongshan Hospital, Fudan University, No. 180 Fenglin Road, Xuhui District, Shanghai 200032, China
• Xiamen Municipal Clinical Research Center for Medical Imaging, No.668 Jinhu Road, Huli District, Xiamen 361015, China

Keywords: Clear cell papillary renal cell carcinoma, Computed tomography, Magnetic resonance imaging, Tumor, Patients, ESRD.

Abstract:

Objective: This study aimed to describe the characteristics of computed tomography (CT) and magnetic resonance imaging (MRI) of clear cell papillary renal cell carcinoma (CCPRCC).

Methods: This retrospective study comprised 27 patients diagnosed with 29 tumors of CCPRCC. The study was approved by the Medical Ethics Committee and the requirement for the informed consent was waived. The inclusion criteria stipulated pathology-confirmed CCPRCCs with at least one preoperative imaging examination, including CT or MRI. Two experienced radiologists independently analyzed the imaging characteristics, including size, location, growth mode, morphology, texture, density, and enhancement pattern. Paired t-test was used to compare differences in CT Hounsfield unit values and apparent diffusion coefficient (ADC) imaging between the tumor and the renal cortex.

Results: The mean age of the 27 patients was 57.0 ± 14.2 years. Nineteen patients underwent CT, while 12 underwent MRI (There are 4 patients underwent not only CT but also MRI). Among the cases, 26 (96%) were single, and 1 (4%) was multiple, consisting of three lesions. Out of the 29 tumors, 15 (52%) were located in the left kidney and 14 (48%) in the right kidney. The mean tumor diameter was 3.3 ± 1.7 cm. Furthermore, 19 (66%), 3 (10%), and 7 (24%) tumors were solid, cystic, mixed solid, and cystic type, respectively. The growth mode was endogenous and exogenous in 8 (28%) and 21 (72%) tumors, respectively. The tumor shape was irregular and round in 5 (17%) and 24 (83%) tumors, respectively. The CT value of the tumor was approximately 33.2 ± 9.8 HU, which was not significantly different from that of the renal cortex(31.1 ± 6.3HU)(p = 0.343). Furthermore, 7 (24%), 12 (41%), and 3 (10%) had calcification, cystic degeneration, and hemorrhage, respectively. In 12 tumors, hypointense and hyperintense were predominant on T1 and T2-weighted images, respectively. The tumor capsule was found at the edge of 12 tumors. The average ADC value of the tumor (1.54 ± 0.74 × 10⁻³ mm²/s) and that of the renal cortex(1.68 ± 0.63×10–3mm2 /s) was not statistically significantly different (p = 0.260). The enhancement scanning revealed “wash-in and wash-out” enhancement in 19 (68%) tumors, continuous or progressive enhancement in 6 (21%) tumors, and enhanced cystic wall and central separation in 3 (11%) tumors.

Conclusion: CCPRCC occurs more likely in middle-aged and elderly individuals, and the tumor is prone to cystic degeneration, with rare bleeding and calcification, and no obvious limitation on MRI diffusion-weighted imaging, which enhancement form performs as mainly “wash-in and washout,” but the final diagnosis depends on histopathology.

Cite this article as:

Huang Shunfa, Tang Qiying, Wu Minrong, Zhong Lianting, Lian Danlan, Ding Yuqin and Zhou Jianjun*, Imaging Characteristics of Clear Cell Papillary Renal Cell Carcinoma: Identifying the Sheep in Wolf’s Clothing, Current Medical Imaging 2024; 20 : e15734056277410 . https://dx.doi.org/10.2174/0115734056277410231206060922