Ultrasonographic and Computed Tomographic Appearance of Spontaneous Cutaneous Fistula Resulted from Retained Surgical Gauze in a Dog

A 6-year-old, spayed female Maltese was presented with the condition of a chronic recurrent abscess formation in the left flank region. Despite the antibiotics and drainage therapy given to the dog, the lesion formed a continued serosanguineous to the point that a purulent discharge was evident. In the meantime, an abdominal ultrasound revealed the presence of a well-defined mass with a hypoechoic outer margin, and a hyperechoic inner rim in the cranial of the kidney. A fistula was noted as being present with a connection between the subcutaneous lesion of the left flank and the abdominal mass. It is emphasized that CT scans revealed the existence of a soft tissue dense mass with low attenuation area, as seen in some internal areas and also a peripheral contrast enhancement was noted within a nonenhancing central region. There was additional nonenhancing fluid found dorsal to the inflammatory tract passing under the epaxial muscles and at the peritoneum. Likewise, the tract exited the skin surface in the left flank. A tentative diagnosis of an abdominal abscess with spontaneous cutaneous fistula was made based on the ultrasonographic and CT appearances. A foreign body such as surgical gauze should always be considered a potential cause of draining tract in small animals, as was considered to be the problem in this case.