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Figure 1—Longitudinal (A) and transverse (B) ultrasonographic images of the abdomen of a 10-year-old 9-kg (19.8-lb) sexually intact male mixed-breed dog with no history or signs of illness evaluated as part of a routine annual examination. Abdominal palpation revealed a large mass in the craniodorsal portion of the right side of the abdomen. Ultrasonographic images were obtained with a 7.5-MHz microconvex array transducer.
History A 10-year-old 9-kg (19.8-lb) sexually intact male mixed-breed dog was brought to its veterinarian for a routine annual examination and vaccination. The dog’s general body condition was good and mental status was bright and responsive; no sign of previous illness was reported by the owner. Abdominal palpation revealed a large mass (approx 10 X 8 X 6 cm), with a firm consistency, occupying the craniodorsal portion of the right side of the abdomen. The dog had no signs of pain in response to palpation of the mass. A moderate neutrophilic leukocytosis was detected on a CBC (82% neutrophils; reference range, 60% to 77% neutrophils). Serum biochemical analysis revealed high serum alkaline phosphatase (112 U/L; reference limit, < 100 U/L) and creatine kinase (241 U/L; reference range, 20 to 150 U/L) activities, a high cholesterol (293 mg/dL; reference range, 140 to 200 mg/dL) concentration, and low glucose (57 mg/dL; reference range, 70 to 110 mg/dL), triglyceride (24 mg/dL; reference range, 40 to 150 mg/dL), and albumin (2.8 mg/dL; reference range, 3 to 5 mg/dL) concentrations. Serum protein electrophoresis revealed low albumin (40.6%; reference range, 53% to 65%) and α1-globulin (1%; reference range, 2% to 5%) fractions and high α2- (19.3%; reference range, 8% to 14%) and βglobulin (21.2%; reference range, 10% to 15%) fractions. The albumin-to-globulin ratio was low (0.68; reference range, 0.79 to 1.35). A dark brown urine sample was obtained via ultrasound-guided cystocentesis. Urinalysis revealed a urine specific gravity of 1.030 (reference limit, > 1.020) and urine protein concentration of 300 mg/dL (reference range, 0 to 30 mg/dL). Leukocytes and RBCs were observed in the urine sediment. Abdominal ultrasonography was performed (Figure 1). Determine whether additional imaging studies are required, or make your diagnosis from Figure 1—then turn the page → This report was submitted by Alessandro Zotti, DVM, PhD; Furio Corsi, DVM; Alessandra Ratto, DVM; and Claudio Petterino, DVM, PhD; from the Department of Veterinary Clinical Sciences, Radiology Unit (Zotti), and Department of Public Health, Comparative Pathology and Veterinary Hygiene (Petterino), University of Padua, 35020 Legnaro, Padua, Italy; Clinica Veterinaria Montecchia, Via P. Schiavo, 20, Selvazzano Dentro, Padua, Italy (Corsi); and I.Z.S. Piemonte, Liguria e Valle d’Aosta, CEROVEC, Piazza Borgo Pila 39, Int. 24, 16129 Genoa, Italy (Ratto). Address correspondence to Dr. Zotti (
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Figure 2—Same ultrasonographic images as in Figure 1. Right-sided severe hydronephrosis and hydroureter are evident; notice the dilated renal pelvis (RP) and ureter (U) and the thin rim of renal parenchyma remaining that is only a few millimeters thick (arrows).
enhancement; the absence of contrast medium within both the pelvis and ureteral lumen was consistent with severe hydronephrosis and hydroureter. No enlarged renal or sublumbar lymph nodes were detected. The absence of masses in the retroperitoneal space and absence of calculi or strictures along the ureter and at the ureterovesicular junction were confirmed on computed tomographic examination. Differential diagnoses included primary neoplasia of the kidney extending to the ureter or vice versa (eg, transitional cell carcinoma [TCC], squamous cell carcinoma, undifferentiated tumor, and metastatic tumor), chronic bacterial ureteritis, granulomatous ureteritis, and ureteral polyps. Comments
Surgical excision of the right kidney and ureter Figure 3—Postcontrast transverse computed tomographic images at the level of the cranial (panel A) and was performed. Grossly, the caudal (panel B) poles of the right kidney of the same dog as in Figure 1. Images were obtained by use of kidney was enlarged. Upon third-generation conventional computed tomography with a slice thickness of 5 mm. Notice that the right longitudinal sectioning of kidney (RK) is markedly enlarged as a result of a dilated renal pelvis and irregular cystic tissue at the caudal pole (window width, 360 Hounsfield units [HU]; window level, 40 HU). The distance between 2 bars of the kidney, a large cyst-like the vertical scale on the right side of images corresponds to 1 cm. The right ureter (U) is also dilated and space filled with dark-red the wall is thickened. A = Aorta. CVC = Caudal vena cava. LK = Left kidney. Asterisk = Left ureter. gelatinous material and marked atrophy of the cortex and medulla was found. The renal pelvis had an irreguDiagnostic Imaging Findings lar and papillate-like surface that contained a mass of white and Interpretation tissue with multifocal areas of necrosis and hemorrhage. The ureteropelvic junction was infiltrated by the same type Severe right-sided renal hydronephrosis and hydroof abnormal tissue. The ureter was markedly thickened ureter is evident (Figure 2). An ultrasonographic scan of throughout its length with an irregular surface, and the luthe retroperitoneal space did not identify a ureterolith or men was narrowed to completely obstructed by the infilany luminal or extraluminal mass surrounding the uretrating white tissue. A histopathologic diagnosis of TCC of ter. No abnormalities were detected on ultrasonography the renal pelvis with infiltration of the ureter was made. of the urinary bladder and ureterovesical junction. The Diagnosis of TCC in the renal pelvis can be challengprimary differential diagnosis was ureteral obstrucing. Histologic examination of biopsy tissue specimens is the tion of unknown etiology with either pyelonephritis diagnostic standard1,2; however, both ultrasonography and or hemorrhage. To further evaluate for ureter obstruccomputed tomography should be considered as valuable dition, the dog was referred for computed tomographic agnostic tools. In the dog of this report, the use of computed examination. tomography allowed for a more detailed examination of abAn enlarged right kidney (9 X 7 X 5 cm) was evident on normalities in the renal parenchyma and urethra. computed tomographic images (Figure 3). The cranial pole The treatment of choice for TCC in the renal pelvis is of the kidney was characterized by a grossly dilated pelvis excision. The prognosis depends on the elimination of the with only a thin rim of renal tissue surrounding a nonenprimary lesion; the prognosis is poor when the tumor is hancing, homogeneous, hypoattenuating content. The metastatic, bilateral, or locally invasive. At 4 months after caudal pole of the right kidney had a polycystic appearance surgery, the patient continued to be in good condition. with similar hypoattenuating content as that of the dilated pelvis and poor peripheral rim enhancement with multiple 1. Dudley RM. What is your diagnosis? J Am Vet Med Assoc 2003;223: mineralized foci. The entire ureteral diameter was uniformly 1731–1732. dilated (0.8 X 0.65 cm) with fluid content similar to that of 2. Militerno G, Bazzo R, Bevilacqua D, et al. Transitional cell carcithe dilated renal pelvis. Both the thickened ureteral wall and noma of the renal pelvis in two dogs. J Vet Med A Physiol Pathol Cin Med 2003;50:457–459. the compressed kidney cortex had poor contrast medium 778
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