Background and objectives: Renal arteriovenous malformation (AVM) is a rare disease and is difficult to be diagnosed by conventional methods because of its rarity. In this study, we investigated the diagnostic clues, and made an algorithm for the better diagnosis of renal AVM. Materials and Methods: We reviewed 13 patients who were diagnosed with AVM by using renal angiography from 1986 to 2020 at our institutes. We evaluated clinical features, diagnostic tools, treatment modalities, and outcomes after the treatment of patients. Results: All patients were female, and the mean age was 36.9 years (range 19 to 54 years). Twelve (92.3%) patients complained of gross hematuria. Four (30.8%) patients showed symptoms in relation with pregnancy and delivery. Angiographic findings demonstrated cirsoid type in 10 patients and aneurysmal type in 3 patients. Among the 11 patients who underwent computed tomography, AVMs were detected in 3 (27.3%) patients. Renal duplex Doppler was performed in 6 patients, and all of these patients were diagnosed with AVM, demonstrating a vascular turbulence or blood-rich area. Twelve patients were initially treated with transarterial embolization. Nephrectomy was performed in two patients due to persistent bleeding with hypovolemic shock. Conclusions: We should consider possible AVMs in patients who were not detected by conventional work up for hematuria, especially in mid-aged, pregnant, or recently delivered women. Renal duplex Doppler might be the optimal diagnostic modality in these patients. Our diagnostic algorithm could be aid to diagnosis and treatment for renal AVM patients.

Tubulocystic renal cell carcinoma (RCC) is a rare subtype of RCC that was recently included in the 2016 World Health Organization classification of tumors of the kidney. Most of these tumors exhibit indolent behavior with low metastatic potential. However, here we report a case of recurrent tubulocystic RCC with aggressive features in the retroperitoneum and contralateral kidney treated with targeted agents and radiofrequency ablation.

Giant multilocular prostatic cystadenoma is a rare benign tumor of the prostate gland that presents as a large retroperitoneal pelvic mass. The mass is usually located between the urinary bladder and rectum, and results in obstructive voiding symptoms and a change in bowel habits. Complete surgical excision is the treatment of choice. We present a case of rapid recurrent giant multilocular prostatic cystadenoma after laparoscopic excision for primary case. A previously healthy 54-year-old man presented with acute urinary retention. Prostate MRI showed a large cystic mass approximately 13 cm in size, multiple septa and lobulation in the prostate, and no visible solid lesions. Laparoscopic marsupialization of giant multilocular prostatic cystadenoma cysts was performed. One year later, the patient presented with local recurrence. Repeated laparoscopic complete resection was performed without any complications and further recurrence. Giant multilocular prostatic cystadenoma has the risk of recurrence in case of incomplete resection. Surgical treatment should be performed with the goal of complete removal following the same principles as cancer surgery.

Urothelial tumors are typically a disease affecting elderly individuals and are rare in young patients. Moreover, upper urinary tract urothelial carcinoma is extremely rare in the young age group. In this study, we present a case of urothelial cell carcinoma of the renal pelvis and ureter in a young man without risk factors of urothelial carcinoma, which was misdiagnosed as ureteropelvic junction obstruction and treated with a laparoscopic pyeloplasty.