title: Occupational bladder cancer in a 4,4 -methylenebis(2-chloroaniline) (MBOCA)-exposed worker.
abstract: A 52-year-old male chemical worker was admitted to the hospital with a history of paroxysmal microscopic hematuria for about 2 years and nocturia with gross hematuria about five times per night for 2 months. He was a nonsmoker and denied a history of any other bladder carcinogen exposure except for occasional pesticide application during agricultural work. Intravenous urogram imaging showed a mass occupying half of the bladder capacity. Cystoscopy revealed a mass over the left dome of the bladder. Cystoscopic biopsy revealed a grade 3 invasive transitional cell carcinoma with marked necrosis. From 1987 until hospital admission in 2001, the patient had worked in a company that produced the 4,4 -methylenebis(2-chloroaniline) (MBOCA) curing agent. He did not wear any personal protective equipment during work. Ambient air MBOCA levels in the purification process area (0.23-0.41 mg/m3) exceeded the U.S. Occupational Safety and Health Administration's permissible exposure level. Urinary MBOCA levels (267.9-15701.1 microg/g creatinine) far exceeded the California Occupational Safety and Health Administration's reference value of 100 microg/L. This patient worked in the purification process with occupational exposure to MBOCA for 14 years. According to the environmental and biologic monitoring data and latency period, and excluding other potential bladder carcinogen exposure, this worker was diagnosed as having occupational bladder cancer due to high exposure to MBOCA through inhalation or dermal absorption in the purification area. This case finding supports that MBOCA is a potential human carcinogen. Safe use of skin-protective equipment and respirators is required to prevent workers from MBOCA exposure.
authors.affiliation: Department of Family Medicine, China Medical University, Taichung, Taiwan, Republic of China.
authors.forename: Chiu-Shong
authors.initials: CS
authors.lastname: Liu
authors.forename: Saou-Hsing
authors.initials: SH
authors.lastname: Liou
authors.forename: Ching-Hui
authors.initials: CH
authors.lastname: Loh
authors.forename: Yi-Chun
authors.initials: YC
authors.lastname: Yu
authors.forename: Shi-Nian
authors.initials: SN
authors.lastname: Uang
authors.forename: Tung-Sheng
authors.initials: TS
authors.lastname: Shih
authors.forename: Hong-I
authors.initials: HI
authors.lastname: Chen
mesh_terms: D002295:Carcinoma, Transitional Cell / Q000139:chemically induced*; D002617:Chemical Industry; D004784:Environmental Monitoring; D006417:Hematuria; D006801:Humans; D008297:Male; D008753:Methylenebis(chloroaniline) / Q000032:analysis / Q000633:toxicity*; D008875:Middle Aged; D009784:Occupational Diseases / Q000139:chemically induced*; D016273:Occupational Exposure; D013624:Taiwan; D001749:Urinary Bladder Neoplasms / Q000139:chemically induced*; D014555:Urination Disorders
chemical_list: D008753:Methylenebis(chloroaniline)