Urachal cyst in a bitch

ABSTRACT

Background: The urachus is a tubular structure continuous with the urinary bladder and the allantois in foetal mammals.It serves as a communication between these two structures. At birth, it loses its function and undergoes atrophy by fibrousproliferation within the lumen. When this atrophy process fails at some point, congenital anomalies of the urachus occur.These anomalies are rare in animals, and to our knowledge, the urachal cyst has not yet been described in dogs. The presentwork is unique in that it reports a case of this congenital defect in a dog. Our aim is to increase awareness and to discussthe clinical presentation, the imaging techniques used, and the final diagnosis of this anomaly.Case A 3-year-old bitch Pit Bull was presented for veterinary assistance to investigate recurrent pseudopregnancy and anirregular estrous cycle. The animal presented in good bodily condition, and the white blood count and clinical biochemistrywere normal. At ultrasound, 2 tubular structures, filled by an echogenic fluid mimicking uterine topography, were foundextending through the umbilical and hypogastric regions. No alterations in structure, echogenicity or echotexture of theother organs were observed, including the ovaries and uterus. On exploratory laparotomy, a cystic structure was found,with 2 segments the larger one was on the left side, attached to the apex of the bladder by its caudal portion; the otherwas on the right side, attached to the spleen by its cranial portion and to the apex of the bladder by its caudal portion inconnection with the left segment. The ovaries, uterus and uterine horns showed no macroscopic alterations. The structurewas removed, and after analysis (macroscopic morphology, wall histopathology and biochemistry of the contained fluid),it was...