Ultrasonographic diagnosis of urachal cyst in three calves.

In 3 calves with irreducible umbilical swelling attributable to urachal cyst, ultrasonography was helpful in establishing a definitive diagnosis. After surgical resection of the persistent urachus, 2 calves recovered without complications. In 1 calf in which the urachus had ruptured subcutaneously during forceful diagnostic palpation, additional surgical debridement of severe skin necrosis, caused by subcutaneous accumulation of urine in the umbilical region, was required. Most irreducible masses of the umbilical area of calves can be classified as attributable to infection, hematoma, or incarcerated umbilical hernia. Urachal cyst should always be considered in the differential diagnosis of an irreducible umbilical mass. Careful palpation of the umbilicus is indicated to avoid the potential complication of iatrogenic rupture of a urachal cyst.