"A 16-year-old female Shih-Tzu, weighing 5 kg, presented with clinical symptoms of abdominal distension and urinary and fecal incontinence. Abdominal palpation detected a large mass. According to the radiographic findings, the bladder had been moved to the umbilicus by the mass and a large abdominal mass was confirmed in the lower abdominal area. Ultrasonography indentified a large heterogeneous mass with heterogeneous parenchyma and a focal anechoic area in the lower abdominal area. The complete blood count abnormalities suggested thrombocytosis and mild neutrophilia, and the serum chemistry indicated an elevated alkaline phosphatase value. During laparotomy, a firm mass that measured $10.5{imes}9.6cm$ was found between the uterine cervix and urinary bladder. The urethra was embedded in the mass. A diagnosis of leiomyosarcoma was established based on histopathology and histochemistry. One week after surgery, urinary retention symptoms that did not appear to be related to mechanical obstruction presented suddenly, but they did not respond to several drug treatments, thus long-term conservative therapy was adopted. The urinary symptoms disappeared on day 27 and the patient started to void large quantities of urine in a smooth and frequent manner. This case report describes the serial changes in the patient's status and the response after surgical remove of the urethra embedding leiomyosarcoma."

Keywords: dog, leiomyosarcoma, urinary incontinence, micturition disorder after surgery.