The role of sonography in the diagnosis and management of urachal abscesses.

Eighteen cases of urachal abscess were studied with sonography. Their configurations were cone shaped in 11 cases, tubular in 4, curved club shaped, and oval and irregular in one each. Their complications, such as intraperitoneal spread, chronic cystitis, and adhesion to the omentum or the colon, could also be suggested by ultrasonography. Gas was found in 50% of the lesions, which were all larger than 1 cm in diameter. An abscess smaller than 1.2 cm in diameter (which can be as long as 5 cm) can be treated with antibiotics or incision and drainage without total excision. A lesion within the extraperitoneal fat space of abdominal wall at the midline below umbilicus suggests the diagnosis of urachal abscess in cases of umbilical discharge and/or when the lesion extends to the umbilicus.