Renal venous malformation misdiagnosed as carcinoma: A report of one case and the review of literature.

The present study reports the clinical data of a patient with renal venous malformation misdiagnosed as carcinoma. CT revealed hematocele in the left renal pelvis and ureter. CTU: the left renal pelvis and calyces showed a slightly high density shadow, a size of about 2.6 cm*1.5 cm, and mild-to-moderate enhancement was found at the edge of the lesion. Enhanced MR showed that irregular mass abnormal signal was observed in the lower calyx of the left kidney and the lesions were cast, with short T1 and slightly long T2 signals. The secondary bleeding or mucus of low-grade malignant tumor became suspicious. The patient underwent cystoscopy and left ureteroscopy under general anesthesia on December 3, 2021. Bloody urine can be seen on the left side, and multiple blood clots in the left renal pelvis can be detected. After washing, dark red bloody necrotic substances can be seen. Pathology suggests that renal venous malformation, accompanied by bleeding and thrombosis, is located in the renal medulla, involving the renal calyx, rupture and bleeding of the renal calyx, and obvious local bleeding of surrounding renal tissue. Follow-up for more than 1 year showed that the patient's condition was stable. When patients have renal colic with hematuria, enhanced CT suggests that renal mass is mild-to-moderate continuous enhancement, enhanced MRI suggests short T1 and long T2, considering that the mass may be accompanied by bleeding, and ureteroscopy suggests that dark red bloody necrotic substances should be considered in the diagnosis of renal venous malformation.