Infraumbilical Midline Mass (Differential Diagnosis as before)

swel_30a_n.jpg: 6.7-year-old girl with a recognizable prominent mass below the navel in the midline. At that moment the navel is inconspicious. swel_30b_n.jpg: Lower abdominal incision; pus is discharged from a preperitoneal cavity. swel_30c_n.jpg and swel_30d_n.jpg: The preperitoneal cavity corresponds to a thick-walled cyst with a chronic inflammation. The cyst lies above the bladder and has a small connection to it. swel_30a_n.jpg to swel_30d_n.jpg: The diagnosis is an urachal cyst with an acute enlargement due to accumulation of pus (acute episode of a chronic inflammation). In case of communication with the bladder it may be the cause of recurrent infections. If the connection is large enough, the changing bladder volume prior to and after voiding may influence the size of the cyst, and by traction on the umbilical ligaments, the aspect of the navel changing from a protruding to a retracted structure.