We report a rare case of colloid carcinoma apparently of urachal deriv
ation. In a patient presenting with nycturia cytological analysis of u
rine led to a tentative diagnosis of colloid carcinoma of urachal orig
in. Endoscopic and radiological investigations confirmed this provisio
nal diagnosis. For this reason, the surgical procedure could be proper
ly planned and restricted to the removal of the apex of the bladder an
d urachus.