Mesothelioma: a study of 22 gases.

: Mesothelioma is a rare, asbestos-associated tumor that infrequently metastasizes. We reviewed 22 autopsies (from February 1989 through July 1994) showing mesothelioma. We determined distribution of metastases and staining characteristics of primary mesotheliomas compared to tissue involved by metastases and/or direct extension. Mean patient age was 68 years (range, 38 to 88 years); black:white patient ratio, 4:18; and male:female patient ratio, 2:1. All patients had a history of asbestos exposure. Fifteen autopsies were complete and 7 were limited to the thoracic cavity. Multiple sites were involved by direct extension. Metastases were in multiple sites, including omentum, stomach, intestine, mesentery, adrenal glands, ovary, pancreas, kidneys, liver, spleen, and vertebrae. Results of immunohistochemical staining of primary mesotheliomas and metastases were similar; both were positive for low-molecular-weight keratin and negative for carcinoembryonic antigen, Leu-M1, Ber-EP4, and periodic acid-Schiff reagent with diastase. Results of testing for high-molecular-weight keratin were variable.