Figure 1.

Morphological and immunohistochemical heterogeneity in mesothelioma. (A) Biphasic mesothelioma consisting of an epithelioid and sarcomatoid component (H&E stain), highlighted by a calretinin staining (B) showing a weaker expression in the sarcomatoid proliferation. (C) Heterogeneous expression of BAP-1 with positive nuclear staining in the sarcomatoid component and loss of BAP-1 expression in the epithelioid areas of the tumor. All pictures were taken at 10× magnification (scale bar: 100 µm).