[Cancer of the bladder occurring in occupational dye users: report of two cases].

Two cases of occupational dye users were found to have bladder tumors. Case 1 was a 32-year-old male, who had worked at the Yuzen process for the last 7 years. Multiple papillary tumors were seen on the whole wall of the bladder endoscopically and total cysto-urethrectomy and ileal conduit were performed. The pathological examination of the bladder tumors revealed non-invasive transitional cell carcinoma grade I--II. His post-operative course has been uneventful without any signs of tumor recurrence for 31 months. Case 2 was a 46-year-old male, who had worked at the throwing stained silk for the last 28 years. He suffered from severe hematuria for six months. A big egg-sized nonpapillary tumor on the posterior wall of the bladder was found and bilateral cutaneous-ureterostomy was performed but severe gross hematuria remained. Total cysto-urethrectomy was performed but the patient died of progressive disease 5 months later. The bladder tumor was a grade III invasive transitional cell carcinoma. The fact that process workers in the dye manufacturing industry have a high risk of bladder cancer has been well known and mass screening examination on them has been systematically performed. Though there is a higher relative risk of bladder cancer in occupational dye users, systematic screening examination has not been done. We emphasize the necessity for establishing systematic mass screening examination of occupational dye users for the early diagnosis of bladder cancer.