Renal pelvic urothelial carcinoma with imaging features presenting as renal infarction 1 case report and literature review

Abstract

Renal pelvic cancer is relatively rare in clinical practice, and renal pelvic cancer characterized by renal infarction is even rarer. We here report a case of renal pelvic urothelial carcinoma with squamous metaplasia with renal infarction as the main imaging feature, and summarize the imaging manifestations of some rare renal pelvic carcinomas.

Conclusion

The imaging features of renal pelvis cancer are diverse and often confused with some benign and malignant diseases, suggesting that extra caution should be exercised in the diagnosis and treatment of renal pelvis cancer.

1 Introduction

Urothelial carcinoma is the fourth most common tumour in Western countries, and upper tract urothelial carcinoma (UTUC) accounts for 5–10 % of all urothelial carcinomas, approximately two-thirds of UTUC occur in the renal pelvis. Renal pelvis cancer is similar in type and morphology to bladder cancer. However, renal pelvis cancer is more aggressive than bladder urothelial cancer, and approximately two-thirds of UTUC are invasive at the time of diagnosis. Therefore, early and accurate diagnosis is of great significance for guiding treatment and improving prognosis.

The symptoms of renal pelvic cancer are variable and non-specific, and diagnosis mainly relies on imaging evaluation. A variety of imaging tests are available for renal pelvis cancer. MRU has high soft tissue resolution, which helps to understand whether the tumour invades surrounding soft tissue organs. It is currently one of the commonly used examinations for the diagnosis of renal pelvis cancer. However, computed tomography urography (CTU) shows high sensitivity (92 %–96 %) and specificity (95 %–99 %), can provide more accurate diagnostic information and is therefore considered the preferred imaging modality for the current diagnosis and staging of UTUC.

Renal infarction (RI) refers to an emergency in which the main or branches of the renal artery interrupt the blood flow of the corresponding blood vessels in the kidney due to embolism or thrombosis, resulting in ischemic necrosis of the kidneys corresponding to the corresponding blood vessels; the incidence of this disease is relatively high Low, clinical symptoms are not specific, and it is easy to be misdiagnosed or missed, leading to irreversible damage to the kidneys. It usually presents as one or more wedge-shaped necrotic lesions, with occluded blood vessels at the top and perirenal bottom. Its histological characteristics are coagulative necrosis with an outline of necrotic tissue. Enhanced CT has certain advantages in distinguishing renal pelvic cancer and renal infarction.

The imaging manifestations of renal pelvis cancer are mostly filling defects of the collecting system. However, the imaging manifestations of some patients with UTUC are also atypical, and the imaging manifestations of many benign and malignant diseases may be very similar to UTUC, so it is easy to be misdiagnosed. Our study reports a case in which imaging features were renal infarction, but postoperative pathological examination revealed invasive renal pelvic urothelial carcinoma with squamous metaplasia. This study focused on exploring the imaging characteristics of renal pelvis cancer under CTU.

2 Case statement

A 63-year-old male was admitted to the hospital with a 1-week history of gross hematuria. There is no history of smoking, no family history of malignant tumours, no history of occupational exposure to carcinogens and no history of chronic diseases. His general condition was good on admission, with no fever, weight loss, or dyspnea. No abnormalities were found on physical examination. The results of laboratory tests such as blood cell analysis, liver and kidney function, and tumour markers were all normal. CTU ( Fig. 1 ) and MRI ( Fig. 2 ) revealed a lesion approximately 8.0 cm in size, with a filling defect in the upper segment of the ureter, showing no significant enhancement. A thrombus is suspected, although tumour involvement cannot be excluded. To rule out thrombotic disorders, further tests for hypercoagulability should be performed, all of which returned negative results. Preoperative diagnosis: renal pelvic tumour with renal infarction (cT3aN0M0), with upper urothelial carcinoma being considered in the differential diagnosis. Taking into account the patient’s overall condition, the tumour’s location, potential vascular invasion, and other factors, the decision was made to proceed with a laparoscopic nephroureterectomy. Postoperative pathological examination showed ( Fig. 3 ): High-grade infiltrating urothelial carcinoma of the renal pelvis with squamous metaplasia, renal capsule invasion, vascular invasion, and nerve infiltration (pT3N0).