Orthotopic ureterocele with concurrent ureteral urothelial carcinoma in a dog

Abstract

A ureterocele is a rare congenital anomaly with cystic dilation of the terminal segment of the ureter entirely within the bladder (orthotopic) or associated with ectopic ureter (ectopic). Its aetiology has not been fully clarified; however, it may involve genetic or acquired factors. Urothelial carcinoma (UC) is the most common type of canine urinary tract neoplasm, among which over 90% of cases are invasive. The non‐papillary (flat) non‐infiltrating form accounts for a very small percentage of canine UCs and is considered carcinoma in situ (CIS). The neoplastic cells of CIS remain within the ureteral mucosa and do not breach the basement membrane. UCs originating from the canine ureter are extremely rare, and no report of a ureteral UC concurrently occurring with a ureterocele has been reported. A 7‐year‐old castrated male Maltese dog weighing 3.5 kg was referred with a 2‐week history of lethargy, anorexia, pollakiuria and intermittent panting. The dog underwent open surgery for removal of bladder calculi 2 years prior, and at the time of the surgery, no other urinary system abnormalities were identified. Ultrasonographic and computed tomographic scans revealed a severely enlarged right kidney and ureter with a ureterocele on the ipsilateral side. A diagnosis of an orthotopic ureterocele causing hydronephrosis and hydroureter was established. Complete nephroureterectomy and ureterocelectomy using the marsupialisation technique were performed. The postoperative histological examination of the excised tissues showed a multifocal carcinoma in situ (non‐papillary non‐infiltrating UC) in the proximal ureter and a fluid‐filled kidney with a thin rim of fibrotic renal tissue. No neoplastic changes were observed in the ureterocele tissue. Postoperatively, the dog recovered rapidly without complications except temporary urinary incontinence, and no evidence of tumour recurrence was detected by ultrasonography performed 6 months after surgery. This case report describes the first case of a dog with an orthotopic ureterocele and ureteral UC, which occurred concurrently at the ipsilateral side of the ureter. The condition was successfully managed with a nephroureterectomy and partial ureterocelectomy.

Right-sided ureteral hemangiosarcoma in a paraplegic dog

“…The clinical signs presented in this report, including abdominal pain upon palpation, apathy, hematuria, anorexia, and vomiting, although nonspecific, resemble cases of malignant ureteral tumors previously reported, such as leiomyosarcoma [14], sarcoma [22], and urothelial carcinoma [23]. Renal dysfunction secondary to the condition or increased pressure in the renal capsule due to hydronephrosis may explain the observed clinical signs, as well as the presence of the tumor itself, considering that signs usually associated with visceral hemangiosarcoma are also vague and nonspecific [1].…”

“…In one case, left nephrectomy and ureterectomy were performed, while in the other, left ureteronephrectomy, partial cystectomy were performed [ 16 , 17 ]. While many factors are involved in the surgical planning for each specific case, the majority of reports involving ureteral neoplasms in dogs resulted in ureterectomy and nephrectomy [ 13 – 17 , 22 , 23 ], making this the first account in which these noble structures were preserved.…”

“…Hemangiosarcoma is a malignant mesenchymal neoplasm that can be classified into visceral and non-visceral types based on its location [18]. Primary occurrence of this type of tumor in the canine ureter is rare [16,17], as are other types of tumors in this region [19][20][21][22][23]. In dogs, only two reports describe primary ureteral hemangiosarcoma [16,17].…”

Ultrasonographic diagnosis of a lymphomatous lymph node presumptively infiltrating the ureter causing hydronephrosis in a 3‐year‐old dog

“…The most common urinary tract neoplasm, urothelial cell carcinoma, is most commonly found in the trigone of the bladder though it can involve the ureter. 1 There are numerous other reports of primary ureteral neoplasms including sarcomas, 2-7 polyps, 8,9 and mast cell tumor. 10 To the authors' knowledge, there is no report of macroscopic invasion of lymphoma into the ureter causing hydronephrosis in a dog.…”

“…Primary and metastatic neoplasms of the urinary tract are rare, especially originating from the ureters. The most common urinary tract neoplasm, urothelial cell carcinoma, is most commonly found in the trigone of the bladder though it can involve the ureter 1 . There are numerous other reports of primary ureteral neoplasms including sarcomas, 2–7 polyps, 8,9 and mast cell tumor 10 .…”