Primary papilloma of the proximal ureter in a 13-year old boy: A rare case

Highlights • Primary papilloma of the ureteral proximal end is extremely rare.• Benign tumors of the ureter are much less frequent than malignant ones.• The main clinical signs of benign ureteral tumor are hematuria, pain and hydronephrosis.• The exact diagnosis can be established with histologic study.• The best noninvasive treatment of benign ureteral mass lesion is a segmental resection of ureter.


Introduction
Primary ureteral papilloma is extremely rare. Urothelial papilloma is a benign exophytic neoplasm that generally does not progress [1,2]. The progression has reported in an association with immunosuppressive therapy [3]. Urothelial papilloma often encountered as a de novo lesion but may arise as a secondary papilloma [4,5]. Urothelial papilloma comprises about 1% of papillary urothelial neoplasms. Most of the patients are less than 50 years old and even can present in children. The male to female ratio is 1.9:1 [4,6]. The most common locations of Urothelial papilloma are posterior or lateral walls of the bladder adjacent to the ureterovesical orifices and also urethra [3][4][5]7,8]. Generally, cystoscopy shows a small unifocal papillary or elevated lesion. Histologically, the structure of urothelial papilloma consists of a delicate fibrovascular core covered by proliferating normal-appearing urothelium lacking atypia, including the presence of umbrella cells with elongated or oval nuclei. Papillae show slender with minimal branching [4,5]. The Recurrence rate of ureteral papilloma of the bladder is about 9-31%, but there is no risk for progression to higher-grade tumors. Hematuria is the most common clinical symptoms [6,9]. Our study has been designed based on the SCARE statement guidelines 2018 [10].  examination. The ultrasonography investigation identified a 1.5 cm heterogeneous hyperechogenic ipsilateral lesion located in the upper segment of left ureter emerging near the ureteropelvic junction. Ultrasonography shows dilation of the right ureter and renal pelvis with moderate hydronephrosis observed (Fig. 1A). The retrograde urography confirmed a 1.5 cm lesion with filling defects in the proximal segment of the right ureter (Fig. 1B). Excretory phase image from an abdominal computed tomography scan demonstrated moderate dilation of the right renal pelvis and calyces, with related cortical atrophy due to hydronephrosis (Fig. 1C). Proximal ureterectomy was done through the right flank incision and sent for histopathological. The formalin-fixed, paraffin-embedded tissue prepared. On the macroscopic study of the specimen, after a longitudinal incision, a sessile mass with a defined margin with 1.5 cm in diameter was exposed in the middle part of the sample was extended along the ureter (Fig. 2A). On histologic examination, there was a papillomatous tumor. Papillae show slender with minimal branching composed of a delicate fibrovascular core with numerous small capillaries which covered by proliferating normal-appearing urothelium lacking atypia (Fig. 2B), including the presence of umbrella cells (Fig. 2C). The pathologic diagnosis was urothelial papilloma, with no evidence of malignant change. The patient had an uneventful recovery with no voice changes. The patient's health as well and the patient's symptoms disappeared. The patient discharged after 3 days and 1 low-pressure suction drains remained in place for 2 days. Follow up done for 2 months with no reported complications. The patient is now in good health.

Discussion
Overall, primary benign neoplasms of the ureters are evidenced by the few instances in the medical literature. Approximately 1 percent of the tumors observed in the upper urinary tract are primary tumors of the ureter. About 250 cases of primary ureteral tumors have reported in the literature [11]. The ureter, like other structures of the urinary tract, could develop neoplasms of epithelial origin. The differential diagnosis of the rarity of the benign urothelial tumor is critical [12,13]. Urothelial papilloma is sporadic in children, and macroscopic hematuria is the essential presenting symptom [14]. Jorge Isaac et al. reported a case of inverted papilloma of the urinary bladder in an 11-year-old. Clinical presentation of their evidence was macroscopic hematuria [15]. Kamarulzaman et al. presented a case of inverted papilloma of the urinary bladder in a 12-year-old girl who complained of intermittent hematuria. The initial ultrasound showed the presence of bladder mass. All clinical signs of patient resolved after endoscopic resection [16]. We present the second case of ureteral papilloma in a 13-year-old boy. Previously, the first case reported by Bocconi-Gibod.

Conclusion
Since primary urothelial papilloma of the ureter is rare in children, the Clinical findings and biologic implications of the tumor are still obscure. Therefore, the risks of local recurrence and progression of this lesion are still uncertain. The study, in more cases and long term clinical follow-up, give us a chance to understand the best diagnostic and treatment methods.

Declaration of Competing Interest
None.

Funding
The research did not receive any funding.

Ethical approval
This case report was approved by the Research Ethics Committee of the Ali asghar pediatric Hospital.

Consent
Written informed consent was obtained from the parents of patient for publication of this case report.

Author contribution
Maryam Rahbar: described in the case report, concept and design of study, acquisition of data, drafting the manuscript, revising the manuscript, and approving the final version of the manuscript.Mahtab Rahbar and Seyed Javad Nasiri: described in the case report, revising the manuscript, and approving the final version of the manuscript.

Registration of research studies
Not applicable.

Provenance and peer review
Not commissioned, externally peer-reviewed.