A in situ carcinoma that involves the urethra. The disease is MONDO_0021285 (carcinoma in situ of urethra). Also known as: carcinoma in situ of the urethra, stage 0 urethra carcinoma, stage 0is carcinoma of the urethra, stage 0is carcinoma of urethra, stage 0is urethra carcinoma, stage 0is urethral cancer, stage 0is urethral cancer aJCC v7, stage 0is urethral carcinoma.