Malignant mesothelioma in young adults.

Ten cases of malignant mesothelioma presenting in patients 40 years old or younger at diagnosis were reviewed. Seven cases had a documented history of asbestos exposure of which five were household exposures. The median age at first exposure to asbestos was 10 years and the median duration of exposure was 120 months. The median latency period (time between initial asbestos exposure and diagnosis of malignant mesothelioma) was 19 years. The median interval from initial symptoms to definitive diagnosis was 5.5 months. The case history of each patient is presented. A significant delay in diagnosis in this age group compared with an age-unrestricted series is noted. The significance of nonoccupational exposure to asbestos is emphasized as a probable causative factor in the development of malignant mesothelioma. In addition, a possible genetic predisposition is briefly discussed.