Squamous cell carcinoma of the urachus. A case report and review of literature.

A rare case of squamous cell carcinoma (SCC) is reported. A cystic tumor, measuring 4 X 4 cm was surgically removed from the supravesical portion in a 77-year-old woman. Macroscopically, it had a communicating canal to the urinary bladder. Microscopically, well differentiated squamous cell carcinoma with pearl formation was noted. An aspiration biopsy was helpful for the histopathological diagnosis at operation. The patient developed purulent peritonitis because of rupture of the tumor which was vulnerable to infection. Six documented cases and the present case were reviewed. The tumors were classified into two types on morphological features: supravesical type and intramural type. Site and local extension of the tumor accounted for clinical features of each type. The authors considered that SCC cells were derived from totipotential epithelial lining of the urachal remnant.