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Plenary Session 4
Saturday 20, November, 2004
09:30 - 12:30, 3 hours, International Conference Hall

Plenary Session 4
Medical Aspects: Surveillance and Treatment of Asbestos-related Diseases
4-A: Asbestos and Non-asbestos Agents in Mesothelioma Pathogenesis and Immunology
Chairs: Yasunosuke Suzuki and Iguchi Hiroshi

Clinicopathological Study on Malignant Pleural Mesotheliomas
Kenzo Hiroshima, Akira Iyoda, Kiyoshi Shibuya, Toshikazu Yusa, Takehiko Fujisawa and Yukio Nakatani
Chiba University, Japan, Chiba Rosai Hospital, Japan

ABSTRACT:
We investigated the clinicopathological features of cases with malignant pleural mesothelioma (MPM), which had been operated at our institutes. There were nine cases in which pleuropneumonectomy had been performed for MPM (1 epithelioid, 3 biphasic, 5 sarcomatoid) during 1995 and 2003. The age of the patients was from 41 to 69 years old, and all were men. Four cases had occupational exposure to asbestos. Five cases were with stage II and four with stage III. The level of hyaluronic acid in pleural effusion was high in most of cases. Tumor cells in epithelioid mesothelioma and in biphasic mesothelioma were positive for PAS staining and Alcian Blue staining, but tumor cells in sarcomatoid mesothelioma were positive for them in only one case. We evaluated the results of immunohistochemical staining according to the histological elements. All of epithelial elements (EE) reacted for cytokeratin AE1/AE3, EMA, and HBME1, however, some of EE reacted for vimentin and calretinin. On the other hand, all of sarcomatous elements (SE) were positive for vimentin and calretin, however, some of SE was positive for cytokratin AE1/AE3 and none was positive for EMA and HBME1. EE and SE were positive for D2-40 in some cases. Five cases were alive and four died after the surgery, and two-years survival was 44%. Immunohistochemical panels, especially calretin, were helpful in the diagnosis of MPM. Although the prognosis for MPM is poor, there are some cases whose prognoses improve with surgical removal of the tumor.