Urinary bladder torsion in a dog with an extraluminal tumor of the bladder apex

A 12‐year‐old, spayed female, Lagotto Romagnolo dog is referred because of acute onset of stranguria, dysuria and abdominal discomfort after jumping from a height. Clinical examination reveals mild abdominal pain with enlargement of the urinary bladder and no hematological abnormalities. Computer tomographic examination identifies a large eccentric soft tissue mass with smooth margins, which contacts the serosal layer of the urinary bladder apex. The urinary bladder is pear‐shaped, displaced laterally, and has a longitudinal spiral pattern (whirlpool sign) in the bladder neck area. Celiotomy reveals a mass attached to the apex of the urinary bladder, which has a clockwise 180° torsion with no signs of necrosis. Partial cystectomy, after detorsion, is performed, and bladder incision is closed routinely. Histopathologic evaluation reveals a grade 1 leiomyosarcoma. Although urinary bladder torsion has been reported in five dogs, neoplastic lesions have not previously described as a cause of torsion and should be included in the differential diagnosis.