Ultrasonographic Features of Presumed Renal Telangiectasia in Three Pembroke Welsh Corgis
ABSTRACT
Renal telangiectasia has been reported in Pembroke Welsh corgis with chronic hematuria; however, the sonographic features of these lesions have never been described. Two dogs with confirmed renal telangiectasia and one dog with presumptive renal telangiectasia were identified in a medical record search. All dogs had one or more variably sized renal nodules identified on abdominal ultrasound. The nodules in two of the three dogs were similar, appearing hyperechoic with numerous punctate hypoechoic to anechoic foci throughout. None of the nodules showed evidence of hemodynamic flow on Doppler ultrasound. Renal telangiectasia should be considered as a benign differential diagnosis, particularly in Pembroke Welsh corgis.
Introduction
Telangiectasia describes chronic dilation of capillary vessels and can be associated with a range of clinical syndromes in dogs and humans. Idiopathic cutaneous telangiectasia has been reported in a golden retriever, and acquired telangiectasia of the urinary bladder and urethra has been reported in dogs that have received intraoperative radiation therapy.1,2 A 1983 case series documented multiorgan telangiectasia in eight Pembroke Welsh corgis with a history of chronic hematuria.3 Histopathologic evidence of telangiectatic lesions were noted in both kidneys of all six dogs that underwent necropsy.
Our goal was to report the sonographic features of both confirmed and presumed cases of renal telangiectasia in three Pembroke Welsh corgis because this has not previously been described in the veterinary literature.
Case Report
Three dogs with confirmed or presumed renal telangiectasia were identified in a search of the electronic medical records at Tufts Cummings School of Veterinary Medicine (TCSVM). No genealogical information was available, but none of the three dogs were known to be related.
Case 1
An 8 yr old, spayed female Pembroke Welsh corgi was referred to TCSVM for hematuria without dysuria and polyuria/polydipsia of ∼6 wk duration. The referring veterinarian had performed several urinalyses, which revealed hematuria and occasional white blood cells. Urine culture was negative. The patient received a course of antibiotics (amoxicillin/clavulanic acid,a 6.25 mg/kg q 12 hr) without improvement. Physical examination was unremarkable.
On initial abdominal ultrasound, punctate mineralized foci were noted in the left renal pelvis and were considered an incidental finding. The kidneys were otherwise considered normal on the limited still images available for review. Cystoscopic examination and biopsy of the bladder wall were recommended; however, they were declined by the owner.
Approximately 2 yr later, the patient returned for evaluation of persistent hematuria. Physical examination was unremarkable. A complete blood count was normal (hematocrit 55%), as was a chemistry profile (blood urea nitrogen 9 mg/dL, creatinine 0.9 mg/dL). On abdominal ultrasound, a rounded, heterogeneous, hyperechoic nodule was identified in the left kidney, measuring 2.2 cm in diameter, with multiple internal anechoic foci throughout (Figure 1A). Mild distension of the renal pelvis (up to 3.3 mm) was noted without ureteral distension. Punctate mineral foci were again noted in the pelvis, which were thought to be unrelated to the nodule. The right kidney and the urinary bladder appeared normal. Fine needle aspiration and biopsy of the renal nodule were discussed but declined by the owner.
Citation: Journal of the American Animal Hospital Association 57, 6; 10.5326/JAAHA-MS-7133
Preoperative thoracic radiographs were unremarkable. Because renal neoplasia (e.g., hemangiosarcoma, renal carcinoma, metastatic disease) was part of the differential diagnosis in this patient, the patient underwent a left nephrectomy the next day. A glomerular filtration rate (GFR) study to ensure sufficient residual function of the right kidney was recommended before the surgery but was declined by the owner. Histopathology of the kidney revealed that a large proportion of the renal interstitium at the corticomedullary junction and extending focally to the cortex was expanded by several, variably sized, dilated, vascular spaces lined by mature endothelial cells (Figure 1B). Vascular spaces contained red blood cells and a smaller amount of other blood elements with occasional luminal fibrin thrombi that were rarely attached to the vessel wall. Vascular channels were surrounded by variable amounts of fibrous connective tissue interspersed with fibroblasts and fewer lymphocytes and plasma cells. The adjacent renal parenchyma was atrophic. These findings were deemed consistent with telangiectasia of Pembroke Welsh corgis.
The patient recovered well and was discharged 2 days after surgery. Additional information obtained from the primary veterinarian, who followed the case for 5 more years, showed no recurrent hematuria until the age of 15 when the patient was euthanized for unrelated reasons.
Case 2
An 11 yr old male castrated Pembroke Welsh corgi was referred to the emergency service at TCSVM for evaluation of an abdominal mass. He had been presented to the referral veterinarian the same day for 2 days of lethargy and anorexia. Before this episode, he had no major medical history. The dog was febrile (40.1°C). Complete blood count showed a mild, nonregenerative anemia (hematocrit 34%, reticulocytes 15 K/μL) and a leukopenia (4.8 K/μL) characterized by a severe neutropenia (0.4 K/μL) with suspected band neutrophils and monocytosis (2.5 K/μL). A complete biochemical profile was unremarkable. A free catch urinalysis documented normal concentrated urine (urine specific gravity 1.032), mild hematuria (3–8 red blood cells/high-powered field) with rare white blood cells (1–4/high-powered field), moderate proteinuria (3+), rare granular and hyaline casts, and occasional cocci. A lateral abdominal radiograph was obtained, which showed a large retroperitoneal mass.
On presentation to TCSVM, this patient remained febrile (39.7°C) and had a grade II/VI left systolic heart murmur. Urine culture was negative for bacterial growth. The repeated complete blood count revealed a mild neutropenia (2.55 K/μL) with left shift and 1–2+ toxic changes as well as a mild thrombocytopenia (6–9 platelet/100× field). Coagulation times were interpreted to be marginally elevated, with citrated prothrombin time 11 s (range: 11–17 s) and activated partial thromboplastin time 129 s (range: 72–102 s).
On abdominal ultrasound, a large (7.2 × 11.1 cm), cavitated mass deformed the cranial pole of the left kidney. There were multiple regions of flocculated, echogenic tissue centrally within this mass, and there was no evidence of hemodynamic flow on Doppler ultrasound of this region. Mild bilateral pyelectasia was noted, and the right kidney was otherwise normal. The urinary bladder and ureters were normal. At the time, the complex left renal mass was suspected to represent an abscess, but the possibility of concurrent neoplasia such as hemangiosarcoma or carcinoma was not completely excluded. Given the ultrasonographic findings and the clinical suspicion of sepsis, surgical exploration was recommended. A GFR study was discussed with the owner but was declined. Thoracic radiographs were normal. Surgical exploration confirmed a large mass associated with the cranial aspect of the left kidney. A sterile swab of the renal mass was taken before the nephrectomy and submitted for aerobic and anaerobic culture, which showed no growth.
On histopathology, the large renal mass was consistent with a chronic hematoma with atrophy of the adjacent renal parenchyma. Bordering the hematoma was a network of prominent, dilated, and irregularly branching vessels, interpreted as a benign vascular malformation suggestive of telangiectasia of Pembroke Welsh corgis. An additional histologic finding of acute neutrophilic vasculitis was identified within some of the sections of kidney evaluated; the significance of this finding in this case is unknown.
The patient was seen by the primary veterinarian for unrelated issues over the following 2 yr. No follow-up urinalysis or blood work was reported.
Case 3
A 5 yr old, castrated male Pembroke Welsh corgi was referred for a several week history of hematuria without dysuria. Urinalysis and urine culture were performed by the referring veterinarian, showing macroscopic hematuria without evidence of bacterial infection. The patient was otherwise healthy, and no abnormalities were identified on physical examination. Complete blood count and chemistry were unremarkable (hematocrit 45%, blood urea nitrogen 14 mg/dL, creatinine 1.0 mg/dL). A von Willebrand factor antigen assay was consistent with a carrier state of von Willebrand disease (vWF:Ag 47%).
On abdominal ultrasound, a 1.1 cm diameter, rounded, inhomogeneous, hyperechoic nodule was identified in the cranioventral aspect of the right kidney (Figure 2A). A similar small (1.2 cm diameter) hyperechoic nodule was also identified in the cranial aspect of the left kidney (Figure 2B). Faint punctate hypoechoic to anechoic foci were noted within both nodules. There was no hemodynamic flow on color Doppler examination of either nodule. Echogenic urinary bladder debris was noted, which was thought to represent blood clots given the history of chronic hematuria. The bladder wall was normal. At this time, renal telangiectasia was considered a top differential considering the signalment and clinical history. Additional differential diagnoses included renal hematoma, carcinoma, or, less likely, renal abscess, or granuloma.
Citation: Journal of the American Animal Hospital Association 57, 6; 10.5326/JAAHA-MS-7133
One month later, the patient returned for a transfusion of cryoprecipitate and recheck ultrasound examination because of persistent hematuria. The previously identified renal nodules were unchanged in appearance. There was similar echogenic debris in the urinary bladder. Renal biopsy was recommended but declined by the owner.
Follow-up communication 8 days after cryoprecipitate transfusion indicated that the client observed no improvement in hematuria. According to records from the referring veterinarian, this patient continued to have waxing and waning hematuria without developing azotemia. The patient was euthanized at the age of 11 yr for unrelated reasons.
Discussion
Renal telangiectasia of Pembroke Welsh corgis is a rare condition often associated with chronic hematuria, first described by Moore et al. in 1983. In this case series, renal lesions appeared as multiple, cavernous, blood-filled spaces with a simple endothelial lining and were noted in both kidneys, as well as multiple other organs.3 These findings were interpreted to represent vascular malformations similar to hemangiomas. A report of a renal hemangioma in a mixed-breed dog describes similar histological features of blood-filled, cavernous spaces lined by flattened endothelial cells.4 Moore et al. suggested that although there is significant overlap between telangiectasia and renal hemangioma on a histological level, a distinguishing feature of telangiectasia is a multifocal, multiorgan distribution. In our cases, the histological designation of telangiectasia over hemangioma was largely because of the patients’ signalment, because histologic examination was only performed on the dogs with no contralateral or extrarenal lesions identified. Another confirmatory microscopic finding in these cases was the poorly circumscribed character of the vascular masses, which would be atypical of hemangiomas.5 Other vascular malformations such as vascular hamartomas and hemangiosarcomas were considered less likely because of the age of the dogs and the lack of endothelial cellular atypia, respectively.
Chronic hematuria is the main reported clinical sign of renal telangiectasia both in this case series and in the study by Moore et al. In two of our three cases, chronic, gross hematuria was reported, and in one dog (dog 2), macroscopic hematuria was identified on urinalysis. Unlike previous reports of renal telangiectasia, none of these three patients had evidence of urinary tract infection. Major complications previously identified included severe anemia (3/8 dogs) and hydronephrosis secondary to ureteral obstruction by a blood clot (1/8 dogs).3 None of the dogs in this case series developed hydronephrosis or severe anemia; however, one dog developed a large renal hematoma of uncertain etiology.
In our study, renal lesions were bilateral in only one dog, whereas they were previously reported in all eight dogs in the 1983 case series.3 The nodules noted in dogs 1 and 3 had similar features, characterized by the presence of numerous punctate, hypoechoic foci throughout a rounded, hyperechoic nodule. There was no evidence of hemodynamic flow within the renal nodules in either of these cases when investigated with color Doppler ultrasound. These hypoechoic foci are thought to represent the dilated blood vessels filled with blood clots as described in telangiectasia. In dog 2, the large, cavitated hematoma likely masked the telangiectatic lesions noted on histopathology.
Differential diagnoses for renal nodules include neoplasia (primary and metastatic), complex cysts, abscesses, or granulomas.6 Primary renal neoplasia makes up 0.6–1.7% of all reported neoplasms in dogs, with 85% of these being epithelial in origin (e.g., renal carcinoma, transitional cell carcinoma, adenoma).7
Ultrasonographic features of renal neoplasia are highly variable.6,8 Renal masses, both benign and malignant, can have homogeneous or heterogeneous echotexture; can be hypoechoic, isoechoic, or hyperechoic; may be ill defined or well defined; and may be rounded or irregular in shape.6 There are few reports of renal hemangiomas in dogs, with limited description of ultrasonographic features.5,7,9 The sonographic features of renal hemangiomas in people include echogenic nodules or masses, although isoechoic masses were also identified in a case series by Lee et al.10 Additional features described in this case series included anechoic areas in the center of these masses, which were thought to correspond to blood-filled spaces on histology. The latter is a similar feature to the cases in our report (dogs 1 and 3).
Renal abscesses are uncommon in dogs, but may be seen in association with pyelonephritis or nephrolithiasis or as a complication of renal biopsy.11 Septic emboli and migrating foreign bodies have also been identified as niduses of renal abscesses, creating lesions that appear inhomogeneous with a hyperechoic rim and centrally decreased echogenicity or as poorly echogenic cavities with internal gas foci and echogenic debris.6,11 However, in our experience and to our knowledge, they do not present as punctate hypoechoic foci within a nodular lesion. Additionally, a case report of a dog with a large pyogranuloma, likely secondary to suture reaction from prior ovariohysterectomy, describes sonographic features of a unilateral, hyperechoic, renal mass.12
Because there is overlap between the appearance of both benign and malignant diseases on ultrasound, tissue sampling should always be considered before considering therapeutic options. Ultrasound-guided core biopsies of renal lesions can be useful to rule out neoplasia; however, surgical wedge biopsies are preferred to preserve the blood vessels and obtain a final diagnosis of renal telangiectasia. In dog 3, sampling was not performed, and therefore, the diagnosis of renal telangiectasia was presumptive and represents a limitation of this study. Renal hemangioma was considered less likely because of the bilateral nature of the lesions. As a genetic carrier of von Willebrand disease, it is conceivable that this patient’s clinical signs were related to a primary hemostatic disorder. However, because there was no reported improvement of hematuria after cryoprecipitate transfusion, this was considered unlikely to be a contributing factor. Although idiopathic renal hematuria could not be ruled out because of the patient signalment and the renal changes identified on ultrasound, renal telangiectasia of Pembroke Welsh corgis was considered the most likely etiology.
In cases of Pembroke Welsh corgis with chronic hematuria, abdominal ultrasound and serial hematocrit measurements are recommended. Because this condition may affect both kidneys, the decision to pursue nephrectomy should be weighed carefully. If nephrectomy is deemed necessary, a GFR study should be recommended before the surgery to ensure sufficient function of the residual kidney.
Conclusion
Renal telangiectasia of Pembroke Welsh corgis has been identified on abdominal ultrasound as an echogenic nodule with anechoic punctate foci that likely represent dilated blood vessels. It is important to list this condition as a differential diagnosis in this breed, because malignant neoplasia may otherwise be suspected, potentially leading to unnecessary nephrectomy. Further prospective investigation is needed to determine prognostic information, etiology and best practices in the treatment of this condition.
(A) Ultrasonographic appearance of the left kidney in dog 1. There is a poorly defined, hyperechoic nodule (between calipers), with numerous punctate anechoic foci throughout. This nodule is in the renal cortex adjacent to the renal pelvis. (B) Photomicrograph of a section through the renal nodule in dog 1, showing a vascular mass at the corticomedullary junction composed of dilated, variably sized, blood-filled, vascular spaces lined by mature endothelial cells. Hematoxylin and eosin stain, 2× magnification.
Ultrasonographic appearance of the right kidney (A) and left kidney (B) in dog 3. Bilaterally, there are poorly defined, heterogeneous, hyperechoic renal nodules with several pinpoint hypoechoic foci.
Contributor Notes
From Cummings School of Veterinary Medicine, Tufts University, Grafton, Massachusetts.
Addendum: This paper was submitted to JAAHA in June 2020, underwent the peer review process, and was officially accepted for publication in January 2021. In October 2020, a paper was published in the journal Veterinárnó Medicína on a similar topic: Noh D, Lee SW, Jung D, Park JK, Lee K (2020): Imaging findings of renal telangiectasia in a Maltese dog. Vet Med-Czech 65, 457–463 (https://doi.org/10.17221/87/2020-VETMED). The editors of JAAHA would like to acknowledge this paper, and also note that the paper published here by Katherine Logwood, VMD, et al. was submitted several months before the publication of the paper by Noh et al.; therefore, JAAHA stands behind the paper by Logwood et al. as original research.
