Allantoic duct (urachal) remnant

Epidemiology and Etiology:

· Remnant of the embryologic duct connecting the bladder urachus to the allantois

Common sites:

·

Gross features:

·

Histologic features:

· Solid clusters of transitional or mucin-producing epithelial cells

· With or without a lumen

· Smooth muscle occasionally

Immunophenotype:

Marker:

Sensitivity:

Specificity:

Molecular features:

·

Other features:

· Patency of this duct with escape of urine from the umbilicus may occur (rare)

References:

· Silverberg SG, DeLellis RA, Frable WJ, LiVolsi VA, Wick MR. Silverberg's Principles and Practice of Surgical Pathology and Cytopathology: 2-Volume Set. 4th ed. Churchill Livingstone; 2005.