Recent trends in the causation of peritoneal mesothelioma: fiber burden analysis of ten cases

Mesothelioma in the past has been strongly associated with a history of asbestos exposure. Studies have shown that, on average, a higher dose of asbestos exposure is required for the development of peritoneal mesothelioma, and a smaller percentage of cases are asbestos related. Non-asbestos-related causes have been reported, including prior therapeutic radiation, genetic predisposition, and chronic inflammation (e.g. Crohn disease, endometriosis, ventriculo-peritoneal shunts, and diverticulitis). Cases in children have also been reported. Recent studies have shown a decreasing trend in fiber burdens and percentage of asbestos-related mesotheliomas, with similar observations in epidemiological studies. We performed fiber burden analysis on lung tissue in 10 cases (six men, four women) of peritoneal mesothelioma since 2010. Fiber analysis was performed using the sodium hypochlorite digestion technique, with asbestos body concentrations determined by light microscopy. Fiber concentrations and types were determined by scanning electron microscopy. The median age for the six men was 62 years (range: 53-75 years). Three cases were epithelioid type and three were biphasic. Two of six cases (33%) had an elevated lung fiber burden, with one case exclusively crocidolite and the other predominately amosite. The median age for the four women was 55 years (range: 39-63 years). Two cases were epithelioid type and two were biphasic. None of the four had an elevated lung fiber burden. Our findings are consistent with contemporary epidemiological studies indicating that a minority of peritoneal mesotheliomas occurring in men are asbestos related and very few are asbestos related in women.