Aspects of Histopathologic Subtype as a Prognostic Factor in 85 Pleural Mesotheliomas

¹ From the Department of Pathology and Cytology, University Hospital, Lund, Sweden
² From the Department of Pulmonary Medicine, University Hospital, Lund, Sweden

Background: The prognosis of patients with pleural mesothelioma is more dependent on "pretreatment factors" than on the effect of therapeutic interventions. Histopathologic subtype is one of several important prognostic factors in pleural mesothelioma, and several studies indicate that the epithelial subtype of pleural mesotheliomas has a more favorable prognosis than the sarcomatoid. In this study, we retrospectively evaluated qualitative and quantitative aspects of the tissue specimens used for histopathologic diagnosis in 85 patients with pleural mesothelioma.

Materials and methods: The prognostic roles of two different histopathologic classification systems were evaluated in 85 consecutive cases of pleural mesotheliomas. Efficiency of different diagnostic procedures, influence of the size of the biopsy specimens on the histopathologic diagnosis, and immunohistochemical profiles for histopathologic subtypes of mesotheliomas were also evaluated.

Results: Patients with pure epithelial mesotheliomas (n=35), and especially those with the tubulopapillary subtype (n=18) of epithelial mesotheliomas, survived significantly longer than those with a sarcomatoid component (n=50). With larger biopsy specimens (surgical biopsy, autopsy), more tumors were classified as biphasic (36/78 vs 9/44, p<0.005). The sarcomatoid mesotheliomas comprised about 20% of the tumors regardless of type of biopsy. Staining intensity for cytokeratin CAM 5.2 was equal in all types of mesotheliomas, while intensity with cytokeratin AE1/AE3 decreased from the epithelial to the sarcomatoid mesotheliomas. Staining with vimentin was most intense among the sarcomatoid mesotheliomas, while with epithelial membrane antigen it was most intense among the epithelial mesotheliomas.

Conclusions: The quality of the biopsy specimens has considerable impact on the possibility to arrive at a correct histopathologic diagnosis. Based on our results, we suggest tubulopapillary mesotheliomas be regarded as "low-grade mesotheliomas" and other types, including the epithelioid type of epithelial mesotheliomas, as "high-grade mesotheliomas." This should be taken into account when designing clinical trials.

Key Words: histopathology • immunohistochemistry • pleural mesothelioma • prognosis

Submitted on December 20, 1994
Accepted on June 22, 1995

This article has been cited by other articles:

				G. Xia, S. R. Kumar, R. Masood, M. Koss, C. Templeman, D. Quinn, S. Zhu, R. Reddy, V. Krasnoperov, and P. S. Gill Up-Regulation of EphB4 in Mesothelioma and Its Biological Significance Clin. Cancer Res., June 15, 2005; 11(12): 4305 - 4315. [Abstract] [Full Text] [PDF]

				A Baldi, D Santini, F Vasaturo, M Santini, G Vicidomini, M P. Di Marino, V Esposito, A M Groeger, G Liuzzi, B Vincenzi, et al. Prognostic significance of cyclooxygenase-2 (COX-2) and expression of cell cycle inhibitors p21 and p27 in human pleural malignant mesothelioma Thorax, May 1, 2004; 59(5): 428 - 433. [Abstract] [Full Text] [PDF]

				P. G. Phillips, G. Asimakopoulos, and M. O. Maiwand Malignant pleural mesothelioma: outcome of limited surgical management Interactive CardioVascular and Thoracic Surgery, March 1, 2003; 2(1): 30 - 34. [Abstract] [Full Text] [PDF]

				V.B. Antony, R. Loddenkemper, P. Astoul, C. Boutin, P. Goldstraw, J. Hott, F. Rodriguez Panadero, and S.A. Sahn Management of malignant pleural effusions Eur. Respir. J., August 1, 2001; 18(2): 402 - 419. [Full Text] [PDF]

				Management of Malignant Pleural Effusions Am. J. Respir. Crit. Care Med., November 1, 2000; 162(5): 1987 - 2001. [Full Text]

				D. B. Campbell Malignant Mesothelioma Ann. Thorac. Surg., May 1, 1997; 63(5): 1503 - 1505. [Full Text]