Abstract
Background:
Ovarian bursal abscess (OBA) is a rarely described, potentially life-threatening condition with a nonspecific clinical presentation, inconclusive first-line diagnostic tests, and no well-defined ultrasonographic features.

Case Description:
A 3.5-year-old intact female miniature Schnauzer was presented with acute lethargy, vomiting, and diarrhea. The physical examination, blood analyses, and abdominal radiographs were nonspecific. Abdominal ultrasound revealed an irregular hypoechoic fluid-filled lesion surrounding the right ovary, focal peritoneal hyperechogenicity, scant free peritoneal fluid, a thin, tubular structure with no Doppler color signal partially encircling the ovary, and bilaterally distended uterine horns with irregular cystic walls. Free fluid obtained by ultrasound-guided aspiration was consistent with septic exudate. A right OBA was presumptively diagnosed. Surgery, histopathology, and culture confirmed an acute suppurative right-sided peri-oophoritis, salpingitis, pyometra, chronic endometritis, endometrial cystic hyperplasia, and septic peritonitis, with Escherichia coli isolation. The patient’s recovery was uneventful.

Conclusion:
Although rare, OBA should be considered a differential diagnosis in intact female dogs due to its potential evolution to septic peritonitis if left untreated. To the authors’ knowledge, this is the first report describing specific ultrasonographic features of an OBA in an intact female dog, which, together with ultrasound-guided abdominocentesis, allowed an early diagnosis. The ultrasonographic findings described here may serve as a reference for similar future cases.

Key words: Escherichia coli; Intact female dog; Ovarian bursal abscess; Oviduct; Septic peritonitis.