Localized (solitary) fibrous tumor of the pleura

Clinical, light microscopic, ultrastructural, and immunocytochemical featur es of localized fibrous tumor of the pleura are reviewed. The differential diagnosis of the: benign tumors can be uncomplicated, but atypical variants and malignant forms require the exclusion of other tumors included in the broad array of spindle cell neoplasms that can arise in or extend to a sero sal surface. Electron microscopy is useful, but immunostaining procedures o ffer more extensive and reliable help in reaching the correct diagnosis. Tu mors histologically similar to localized fibrous tumor of the pleura have b een described in a number of extraserosal locations. Some localized fibrous tumors may be true fibromas, whereas the typical pleural tumor appears to arise from the subserosal mesenchymal cell and is composed of CD34-positive cells which are more primitive in their morphology than mature fibroblasts .