Malignant neoplasm of urachus

This code identifies a primary cancerous tumor originating in the urachus, a remnant of the allantois that connects the fetal bladder to the umbilicus. Urachal carcinoma is a rare form of bladder cancer, often presenting with hematuria or a palpable mass.

Assign this code when documentation clearly indicates a primary malignant neoplasm arising from the urachus. This diagnosis is typically confirmed through biopsy and imaging studies such as CT or MRI. Use for cases where the tumor is specifically identified as urachal in origin, rather than a general bladder malignancy.

• Differentiate from other bladder malignancies (C67.0-C67.9) which are more common.
• Ensure documentation specifies "urachus" as the primary site, not just "bladder."
• Code any associated metastases separately, following primary site coding guidelines.