Unilateral hydronephrosis and hydroureter secondary to ureteric atresia, and uterus unicornis in a young terrier.

A nine-month-old entire female terrier cross was presented with intermittent anorexia, vomiting and recent onset of abdominal pain and distension. A diagnosis of unilateral hydronephrosis was made following ultrasound examination and intravenous urography, but no cause was identified. Subsequent ureteronephrectomy and histology of the affected kidney showed ureteric atresia as the cause of obstruction. Uterus unicornis was also identified and ovariohysterectomy was performed. The combination of structural abnormalities can be explained by an in-utero developmental error of their common embryological precursor, the mesonephric duct.