A case series of urinary bladder rhabdomyosarcoma in seven dogs.

Background: Juvenile urinary bladder rhabdomyosarcoma (ubRMS) is a known entity; however, literature regarding its clinical behavior and endoscopic features is scarce. The aim of this study was to describe clinical and endoscopic features, and outcomes of ubRMS in dogs. Case Description: Dogs undergoing transurethral endoscopy and with a histological diagnosis of ubRMS were retrospectively collected. Seven dogs with a median age of 18 months (range 6-32 months) were included in this retrospective, multicenter, and descriptive study. Median tumor size was 58 mm (range 30-65 mm), and tumor location was bladder neck in three cases, trigone in two cases, and bladder body in two cases. Two dogs had monolateral ureteral obstruction. Two dogs presented with regional lymphadenopathy and one dog had lung lesions suggestive of metastatic disease. A grape-like mass was reported in four cases and solid in two, with variable consistency (two friables, two firms, and two not reported). Tumor treatments included surgery in three cases, surgery, and adjuvant doxorubicin in one case, and palliative therapy in three cases. The overall median survival time (ST) was 45 days. STs were shorter (range 20-45 days) for dogs treated with palliative care than for dogs treated with curative-intent treatment (range 70-120 days). Conclusion: ubRMS should be considered as a differential diagnosis in young dogs presenting with bladder masses. In this study, ubRMS confirmed its aggressive clinical behavior. Surgery and chemotherapy seem to increase STs but the prognosis remains poor.

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.