Photograph of cadaver dissection showing the umbilical structures on a view of a partially reflected anterior abdominal wall.
Explanation to Objectives Objectives The development and normal progression of the urachus including its remnant in the adult.The differential diagnosis of an urachal cyst.How a pathologist would be able to determine that the extirpated structure was derived from the urachus.The potential complications of an urachal cyst. Urachus The urachus is a fibrous embryonic connection between the urinary bladder and the umbilicus. It is the remnant of an earlier embryologic structure, the allantois. In the adult the urachus is known as the median umbilical ligament (Figure 5) a fibrous cord deep to the transversalis fascia, which remains connected to the bladder and the umbilicus. Urachal cyst differential diagnosis The differential diagnosis for an urachal cyst in an adult would include vitelline duct anomalies, appendicitis, granulomatous inflammations, and granulation tissue from the umbilical stump. Pathological confirmation Microscopic analysis of the cyst could make the diagnosis that this structure was a urachal rather than a mesenteric cyst (also would be attached to mesentery) because the lining cells of a urachal cyst are urothelium(transitional epithelium), as would be expected based on the embryological origin of this cyst (Figure 6). In contrast, mesentericcysts would likely be lined by a mesothelium (simple cuboidal or squamous epithelium typical of mesenteric lining).
