Author: Assoc Prof Patrick Emanuel, Dermatopathologist, Auckland, New Zealand, 2013.
Failure of complete urachal lumen closure causes urachal cysts or a free communication between the bladder and the urachus in which urine leaks from the umbilicus.
Histology of urachal cyst
These are lined by urothelium, cuboidal, flat or atrophic epithelia (figures 1, 2, 3). The cyst may be located at any point between the bladder and the umbilicus. The surrounding dermis or soft tissue often shows fibrosis, calcification and reactive changes (figures 1, 2, 3)