Discussion:
The urachus is a fibrous residue of the allantois that connects the bladder to the umbilicus. The involution of this structure usually occurs after birth in the form of an obliterated fibrous cord. Urachal cyst is a sub umbilical fluid collection due to the accumulation of serous secretions and blood. A urachal cyst is usually diagnosed by umbilical flow or umbilical pyogenic granuloma in newborns, and exceptionally it may remain latent and be diagnosed in adulthood.  The persistence of this cyst can be revealed by complications like infection, as in our case. The exploration of the urachal cyst is essentially based on abdominopelvic ultrasound and the treatment is based on surgical excision in order to prevent the risk of infection and neoplastic degeneration.