2002 年 41 巻 4 号 p. 298-299
We report 2 cases of urachal carcinoma having totally different cytological features. Tumor cells in case 1 were highly atypical. having scanty mucin in the cytoplasm and growing in papillary patterns. Tumor cells in case 2 showed mild atypia with abundant mucin. Case 1 was difficult to distinguish cytologically from poorly differentiated transitional cell carcinoma. Case 2 was difficult to distinguish from adenoma. A definitive diagnosis of urachal carcinoma having these cytological features can only be made combining characteristic clinical findings.