Original ArticleLocalized Malignant MesotheliomaAllen, Timothy Craig MD, JD*; Cagle, Philip T MD*; Churg, Andrew M MD†; Colby, Thomas V MD‡; Gibbs, Allen R MD§; Hammar, Samuel P MD∥; Corson, Joseph M MD¶; Grimes, Margaret M MD**; Ordonez, Nelson G MD††; Roggli, Victor MD‡‡; Travis, William D MD§§; Wick, Mark R MD∥∥Author Information From the *Department of Pathology, Baylor College of Medicine, Houston, TX; †Department of Pathology, University of British Columbia, Vancouver, British Columbia, Canada; ‡Department of Pathology, Mayo Clinic Scottsdale, Scottsdale, AZ; §Department of Histopathology, Llandough Hospital, Penarth, Vale of Glamorgan, United Kingdom; ∥Diagnostic Specialties Laboratory, Bremerton, WA; ¶Department of Pathology, Harvard Medical School, Boston, MA; **Department of Pathology, Virginia Commonwealth University Medical Center, Richmond, VA; ††Department of Pathology, University of Texas MD Anderson Cancer Center, Houston, TX; ‡‡Department of Pathology, Duke University Medical Center, Durham, NC; §§Armed Forces Institute of Pathology, Washington, DC; and ∥∥Department of Pathology, University of Virginia, Charlottesville, VA. Reprints: Andrew Churg, MD, Department of Pathology, University of British Columbia, 2211 Wesbrook Mall, Vancouver, BC V6T 2B5, Canada (e-mail: [email protected]). The American Journal of Surgical Pathology: July 2005 - Volume 29 - Issue 7 - p 866-873 doi: 10.1097/01.pas.0000165529.78945.dc Buy Metrics Abstract Localized malignant mesotheliomas are uncommon sharply circumscribed tumors of the serosal membranes with the microscopic appearance of diffuse malignant mesothelioma but without any evidence of diffuse spread. Little is known about their behavior. We report 23 new cases. The mean age at presentation was 63 years, and the sex ratio was approximately 2:1 (male/female). Twenty-one tumors were pleural and 2 were peritoneal. Sixteen tumors reproduced microscopic patterns of diffuse epithelial mesotheliomas, 6 had mixed epithelial and sarcomatous patterns, and 1 was purely sarcomatous. After surgical excision of the tumor, 10 of 21 patients with follow-up data were alive without evidence of disease from 18 months to 11 years after diagnosis. Patients who died had developed local recurrences and metastases, but none had diffuse pleural spread. Localized malignant mesotheliomas should be separated from diffuse malignant mesotheliomas because of their localized presentation, quite different biologic behavior, and far better prognosis. © 2005 Lippincott Williams & Wilkins, Inc.