A 13-year-old, intact male, Yorkshire terrier dog with oliguria and hematuria was presented to the Small Animal Clinic at the Gyeongsang National University animal medical center. There were no remarkable findings on serum chemistry values and complete blood counts. Abdominal radiographs revealed mild elevation of the descending colon at the pelvic level. On the excretory urographic images, a large filling defect was identified in urinary bladder with narrow urinary bladder wall contact and there were no remarkable findings in kidneys and ureters. The abdominal ultrasonography revealed that an irregularly marginated, heterogeneous mass in urinary bladder, central cavitary lesion and mild vascular flow were also observed. Computed tomography showed a heterogeneously attenuated mass within urinary bladder. The mass was surgically excised, and leiomyosarcoma was confirmed by histopathological examination. The patient was followed up for two months and there were no complications. This case is of interest because of the unusual findings of leiomyosarcoma of urinary bladder in a small breed dog.

Keywords: leiomyosarcoma, urinary bladder, ultrasonography, computed tomography, dog