Pleural fibroma is differentiated from mesothelioma by the presence which of the following in the former- (PGI June 2011)
Pleural fibroma (Benign fibrous mesothelioma)
a. Microscopically, the tumors show whorls of reticulin and collegen fibers among which are interspersed spindle cells resembling fibroblasts.
b. The tumor cells are CD 34 ( + )ve and keratin negative by immunostaining. This feature can be diagnostically useful in distinguishing these lesions from malignant mesothelomas which is CD34 ( - )ve and keratin positive.