Uncommon Spindle Cell Tumors of the Pleura

The occurrence of spindle cell tumors of the pleural other than the conventional sarcomatoid mesothelioma or solitary fibrous tumor, is rather unusual. Clinically and radiologically, patients with these tumors may show similar features as those associated with the more common neoplasms of the pleura. Therefore, histopathologic assessment of those lesions is highly important. However, it is also important to highlight the role that immunohistochemistry plays in separating these tumors, as some of these neoplasms may show similar immunophenotype with mesothelioma. Even though in most of these cases, the use of immunohistochemistry can provide valid information to properly separate these tumors, in some more unusual circumstances, the use of molecular techniques may further aid in the characterization of these tumors. Nevertheless, it is highly important not only to acknowledge the existence of these tumors arising primarily in the pleura but also to keep them in the differential diagnosis of primary spindle cell neoplasms of the pleura.