tissue and fibrosis.25 This is because in reactive
states submesothelial spindle cells acquire
cytokeratin intermediate filaments, usually of
low molecular weight, while retaining their
connective tissue markers and so stain for both
cytokeratin and vimentin.132526 The same pattern
of staining is seen in most sarcomatoid
mesotheliomas.
In inflammatory pleural lesions there is
usually active granulation tissue formation
with an acute and chronic inflammatory infiltrate
and fibrosis. The fibrosis does not have a
storiform or basket weave appearance and
nuclear hyperchromatism is not a feature.