Ultrasound-guided catheter biopsy of the lower urinary tract: technique and results in 12 dogs

Usefulness of squash preparation cytology in the diagnosis of canine urinary bladder carcinomas

BACKGROUND

Epithelial cells show varying degrees of cytologic atypia in dogs with nonmalignant lesions (NML) and carcinomas (ubC) of the bladder, making histopathologic examination necessary for a definitive diagnosis.

OBJECTIVES

This study aimed to investigate the diagnostic performance of squash preparation cytology and identify several cytomorphologic features of ubC to assist in diagnoses.

METHODS

Squash preparations were made and reviewed in dogs that underwent transurethral cystoscopy. The results were compared with histopathologic diagnoses. Two cytopathologists performed blinded assessments using a scoring system established for 11 cytologic features, including the presence of macronuclei, abnormal nucleoli, atypical mitoses, signet ring cells, multinucleated cells, nuclear molding, anisokaryosis, cytoplasmatic microvacuolization, cell arrangements, and neutrophil and lymphocyte infiltrations. Based on cytologic and histopathologic diagnoses, dogs were divided into ubC and NML groups. Associations between cytologic and histopathologic diagnoses were investigated, and agreement between the cytopathologists was calculated. Cytologic features were analyzed with multivariate logistic regression models. The performance of predictors in the final model was evaluated in terms of Sensitivity (Se), Specificity (Sp), accuracy, positive predictive value (PPV), negative predictive value (NPV), likelihood ratio positive (LR+), and negative (LR-) values, and the diagnostic odds ratio (DOR).

RESULTS

Forty-four dogs diagnosed with ubC, and 17 with NML were included in the study. Cytologic and histopathologic diagnoses were significantly associated with each cytopathologist. There was an almost perfect agreement between cytopathologists (κ = 0.88). The absence of neutrophilic infiltration, the presence of multinucleated cells, and nuclear molding were associated with ubC; using a combination of these features in parallel testing resulted in Se = 0.98, Sp = 0.65, accuracy = 0.89, PPV = 0.88, NPV = 0.92, LR + =2.77, LR- = 0.04, and DOR = 7.7.

CONCLUSIONS

Squash preparation cytology could be a reliable technique to diagnose ubC in dogs. The best diagnostic combination was the absence of neutrophilic infiltration, multinucleated cells, and nuclear molding.

Ultrasound-guided transurethral urinary bladder biopsy using an endoscopic biopsy forceps in dogs: 27 cases (2016-2019)

OBJECTIVES

To describe an ultrasound-guided transurethral bladder biopsy technique using endoscopic forceps and its results in dogs of different sizes with different lesion locations.

MATERIALS AND METHODS

Medical records of dogs that underwent ultrasound-guided transurethral bladder biopsy with endoscopic forceps were retrospectively reviewed. Patient signalment, lesion location, use of urinary catheter as a guide, outcome of the procedure and histopathology results were retrieved.

RESULTS

Twenty-seven dogs underwent this procedure. Biopsy samples were successfully obtained in 23 dogs. Insertion of the endoscopic forceps without a urinary catheter allowed the procedure to be performed in patients with a small urethral diameter without complication. The procedure was unsuccessful in dogs with a urethral diameter smaller than the outer diameter of the biopsy forceps (i.e. 1.8 mm), either due to small patient size or obstructive urethral lesion. All biopsy samples allowed histopathological diagnosis. No complications were reported after the procedure.

CLINICAL SIGNIFICANCE

This non-invasive biopsy technique should be considered in patients with bladder lesions in which histopathological diagnosis is needed, especially when endoscopic examination is not feasible. By use of the Doppler mode, biopsy retrieval was safe also when the lesion ​was highly vascularised.

Lower Urinary Tract Neoplasia

Lower urinary tract neoplasia in companion animals is a debilitating and often life-threatening disease. Tumors of the bladder, urethra, and prostate often occur independently, although extension of these tumors into adjacent regions of the lower urinary tract is documented frequently. The most common lower urinary tract tumor in dogs and cats is transitional cell carcinoma (TCC). In both dogs and cats, TCC affecting the urinary bladder is generally considered to be highly aggressive with both local and metastatic disease potential, and this disease poses unique treatment challenges. Whereas much literature exists regarding the TCC disease process, treatment options, and prognosis in dogs, relatively few studies on feline TCC have been published due to the lower incidence of TCC in this species. Prostate tumors, most commonly adenocarcinomas, occur less commonly in dogs and cats but serve an important role as a comparative model for prostate neoplasia in humans. This article serves as a review of the current information regarding canine and feline lower urinary tract neoplasia as well as the relevance of these diseases with respect to their human counterparts.

Ultrasound-Guided Urinary Bladder Biopsy Through a Urinary Catheter in a Bitch

A 34.4 kg 5 yr old spayed female mixed-breed dog was presented for evaluation of a urinary bladder mass. The dog had a recent onset of hematuria and stranguria but otherwise appeared to be healthy. Abdominal ultrasound revealed a mass in the urinary bladder. The dog was sedated and a 10-French rubber catheter that had the blunt end removed was passed from the urethra to the urinary bladder. Using ultrasound guidance, ellipsoid cup biopsy forceps were advanced through the rubber catheter to the urinary bladder mass and biopsies were successfully obtained. The dog was discharged from the hospital a few hours after the procedure. Histopathology of the mass was consistent with polypoid cystitis. Follow-up surgical removal of the polyp was uneventful, and histopathology confirmed the presurgical biopsy diagnosis. Procurement of urinary bladder biopsies through a urinary catheter with ultrasound guidance was used as a minimally invasive alternative to either cystoscopy or surgery in a bitch. Use of this technique achieved a diagnosis without the need for specialized endoscopic equipment, anesthesia, or surgery.

Avaliação ultra-sonográfica e pelo Doppler colorido do carcinoma de células transicionais da bexiga em cães

Estudaram-se os aspectos ultra-sonográficos das lesões sugestivas de carcinoma de células transicionais (CCT), investigou-se a contribuição do mapeamento Doppler colorido e de amplitude no diagnóstico das lesões sugestivas de CCT e verificou-se a acurácia do método de biópsia ecodirigida por sucção traumática via sondagem uretral na coleta de material para confirmação diagnóstica CCT da bexiga. Para tal, foram selecionados nove cães que atendiam aos critérios de inclusão determinados. Destes, sete apresentavam CCT. A ultra-sonografia permitiu a detecção de massas exofílicas com características vegetantes em cinco cães, e de lesões infiltrativas na parede vesical estendendo-se para a uretra em dois. Pelo exame com Doppler colorido e de amplitude, constatou-se a vascularização interna da massa, indicativa de neoangiogênese tumoral, em quatro animais. A técnica de sucção traumática por aspiração permitiu a elucidação diagnóstica em cinco dos sete animais com CCT. Concluiu-se que, na maioria dos casos, a ultra-sonografia propicia a identificação de lesões sugestivas de CCT, constituindo a primeira técnica de diagnóstico por imagem indicada para pacientes que apresentem hematúria e disúria.

Development, advances and applications of diagnostic ultrasound in animals

Ultrasound has many industrial applications but it was first introduced as a medical diagnostic aid in the 1940s with its first veterinary application, the detection of ovine pregnancy, being reported in 1966. Since then, improvements in equipment quality combined with an increased awareness of the benefits of ultrasound as an imaging technique have led to its widespread use in the veterinary field. Recent advances in computer technology have significantly influenced equipment design and the miniaturization of transducers allows intra-operative and intra-vascular applications. Software advances have improved the ability to manipulate and process data, leading to an increased amount of information being obtained from each examination and the advent of 'remote diagnosis'. Ultrasound guided interventional techniques can now be used for diagnostic or therapeutic purposes. Many of these developments have been introduced by equipment manufacturers but have found specific applications in the veterinary field. Ultrasound is currently employed in a very diverse range of situations, not just as a diagnostic tool in the routine clinical workup of a range of species, but also for disease screening, conservation projects, commercial services, herd management and clinical research.

Diagnostic approach to hematuria in dogs and cats

Hematuria indicates the presence of urogenital disease in dogs and cats. Persistent hematuria (macroscopic or microscopic) should be evaluated to determine the source of bleeding and the underlying cause so that appropriate treatment can be recommended. Results of the history and physical examination often help to localize disease to the urinary tract (either upper or lower) or genital tract. Additional diagnostic evaluation, including laboratory testing(eg, urinalysis, urine culture), diagnostic imaging (eg, abdominal radiographs, ultrasound), and collection of tissues for cytologic or histopathologic evaluation, may be needed to identify the underlying cause. If a thorough evaluation fails to reveal the source or cause of hematuria, exploratory celiotomy should be considered,especially if idiopathic renal hematuria is possible.

Management of transitional cell carcinoma

Canine TCC of the bladder is a disease for which early detection and multimodality therapy are likely to produce the most favorable results. Urine screening tests are being investigated as tools to permit earlier detection. The possibility of tumor seeding must be considered when obtaining urine for analysis and when performing surgery. Because these tumors tend to be very locally invasive at the time of diagnosis and are likely to metastasize, cures are unlikely. Currently, combination protocols using chemotherapy and the nonsteroidal anti-inflammatory agent piroxicam show the most promise in producing tumor responses. Surgery and radiation therapy are useful treatment modalities in select cases. Despite advances in treatment of canine TCC, median survival times reported for prospective clinical trials have never exceeded 1 year, regardless of the treatment modality. Development of accurate tests for early tumor detection could have a significant impact on the success of treatment of this tumor in canine patients.

Needle-tract implantation following us-guided fine-needle aspiration biopsy of transitional cell carcinoma of the bladder, urethra, and prostate

Localized tumor implantation of the ventral abdominal wall was found at 2, 5, and 8 months following percutaneous ultrasound-guided fine-needle aspiration biopsy (FNAB) of transitional carcinoma of the bladder, urethra, or prostate in 3 dogs. To our knowledge this complication has not been reported in dogs following FNAB. Despite the rarity of needle-tract implantation, the potential for this complication with transitional cell carcinomas is apparently not negligible and warrants consideration. We recommend traumatic urethral catheterization to obtain a cytologic diagnosis of potential transitional cell carcinomas of the lower urinary tract or prostate whenever possible until more information becomes available. However, needle-track implantation is so rare that it should not influence the decision to perform a percutaneous FNAB if the urethra cannot be catheterized.

Ultrasonography of urinary bladder disorders

Ultrasonography is often recommended as the first diagnostic imaging modality in patients with hematuria or dysuria. It can provide information relative to the capacity of the urinary bladder, changes in bladder outline, changes in wall thickness, identification of mural and luminal masses, and identification of extrinsic lesions that may displace the bladder wall causing changes in its shape. Ultrasonography allows an evaluation of the entire urinary tract (except distal urethra) in both female and male dogs as well as the sublumbar region for lymphadenopathy.