Monarch Disease Ontology id MONDO_0021041 (pleural solitary fibrous tumor) is a localized neoplasm of probable fibroblastic derivation, that arises from the pleura. It is characterized by the presence of round to spindle-shaped cells, hylanized stroma formation, thin-walled branching blood vessels, and thin bands of collagen. Also known as: fibroma of pleura, fibroma of the pleura, localised fibrous mesothelioma of pleura, localised fibrous mesothelioma of the pleura, localized fibrous mesothelioma of pleura, localized fibrous mesothelioma of the pleura, pleura solitary fibrous tumor, pleura solitary fibrous tumour.