Improving the Accuracy of Mesothelioma Diagnosis in China

Abstract

Introduction: In the Western world, malignant mesothelioma (MM) is most prevalent in the pleura of older males who have been professionally exposed to asbestos. Information about MM from rapidly industrializing countries such as China is minimal. There is concern that a proportion of MM diagnoses in China may be incorrect because most Chinese physicians do not have experience diagnosing this rare cancer. We recently reported an unusually high incidence of peritoneal MM among eastern Chinese female patients. Here, we review the accuracy of MM diagnoses in China and provide suggestions to improve the accuracy of diagnosis.

Methods: We reviewed 92 pathological diagnosis of MM in 2002-2015 from two reference centers in the province of Zhejiang in eastern China. We performed a large set of immunohistochemistry analyses to increase the reliability of the diagnosis.

Results: We confirmed the MM diagnosis in 12 of 34 of the pleural tumors (35.3%), in 38 of 56 of the peritoneal tumors (67.9%), and in two of two of the MMs of the tunica vaginalis (100%). MMs were characterized by tumor cells showing nuclear Wilms tumor 1 and calretinin staining and by strong membranous staining for cytokeratin CAM5.2. The results of staining for the epithelial markers carcinoembryonic antigen, thyroid transcription factor-1, MOC31, BerEP4, p63, p40, paired box 8, ER and PR were negative. BRCA1 associated protein 1 nuclear staining was lost in percentages similar to what has been reported for samples from Western countries.

Conclusions: Our findings suggest that MM-especially in its pleural localization-is often misdiagnosed in eastern China. Identifying pitfalls and possible solutions in the pathological diagnosis of MM will affect both the standard of care and research in China.

Keywords: BAP1; China; IHC; Mesothelioma.

Figure 1. Immunohistochemistry: Epithelial MM and Lung adenocarcinoma

Left column: Epithelial MM with Calretinin, WT-1, D2-40, CAM5.2 positive,CD15,TTF-1, negative. Right column: Lung Adenocarcinoma, CAM5.2, CD15, TTF-1 positive; Calretinin, WT-1, D2-40 negative. Original magnification 100×. Inserts at right lower corner, original magnification 400×.

Figure 2. Immunohistochemistry: Biphasic MM and Carcinosarcoma of Kidney, both showing a clear cell component

Left column Biphasic MM, Calretinin and D2-40 positive, WT-1, CAM5.2, CD15,TTF-1 negative. Right column Carcinosarcoma of Kidney, CD15, PAX-8 positive; Calretinin, WT-1, D2-40 negative, CAM5.2 negative/weakly positive. Original magnification, 400×.

Figure 3. Expression of BAP1 and INO80 in MM

Top row: MM, epithelial type, showing negative nuclear staining for BAP1 and for Ino80. Middle row: Biphasic MM showing homogeneous BAP1 and Ino80 nuclear staining. Bottom row: Sarcomatoid MM showing focal nuclear staining for BAP1 and for Ino80. Original magnification 400×. Arrows point at tumor cells showing nuclear staining.