Imaging diagnosis and differential diagnosis of renal cancer

Because there are many imaging methods for kidney cancer, preoperative diagnosis is usually not difficult. However, misdiagnosis and mistreatment still occur from time to time, sometimes resulting in irreparable mistakes, so we must pay attention.

1. Renal cyst: Typical renal cysts can be easily distinguished from renal cancer by imaging examinations, but when there is bleeding or infection in the cyst, it is often easily misdiagnosed as a tumor. Some renal clear cell carcinomas are uniform inside and have very weak low echoes, which can be easily misdiagnosed as very common renal cysts during physical examination screening. Cloix reported the results of surgical exploration of 32 cases of "complex cystic lesions in the kidney", and found that 41 of them were renal cancer. For benign renal cysts with irregular thickening of the cyst wall and high central density, it is difficult to distinguish them using any of the above examination methods alone, and it often requires comprehensive analysis and judgment. If necessary, a puncture biopsy can be performed under the guidance of B-ultrasound. It is not advisable to easily give up follow-up or perform surgery recklessly.

2. Renal Hamartoma: Also known as renal angiomyolipoma, it is a relatively common benign renal tumor. With the widespread development of imaging examinations, it is increasingly seen in clinical practice. Due to the presence of fat components in typical hamartomas, qualitative diagnosis can be made on B-ultrasound, CT and MRI images, and it is easy to distinguish from renal cell carcinoma clinically. B-ultrasound of renal hamartoma shows that there are medium-strong echo areas in the mass, and CT shows that there are areas with negative CT values ​​in the mass, which are still negative after enhanced scanning. Angiography shows that after injection of adrenaline, the tumor blood vessels shrink together with the kidney's own blood vessels; B-ultrasound of renal cell carcinoma shows that the mass is medium-low echo, and the CT value of the mass is lower than that of normal renal parenchyma. After enhanced scanning, the CT value increases, but not as obvious as normal renal tissue. Angiography shows that after injection of adrenaline, the kidney's own blood vessels shrink, but the tumor blood vessels do not shrink, and the tumor blood vessel characteristics are more obvious.