About 80% of pleural<unk> s originate in the visceral pleura, while 20% arise from parietal pleura. Although they are often very large<unk> s (up to 40 cm. in diameter), over half are asymptomatic at diagnosis. While some researchers have proposed that a<unk>  occupying at least 40% of the affected hemithorax be considered a "giant<unk> ", no such "giant" variant has yet been recognized within the most widely used pleural<unk>  classification scheme. Some<unk> s are associated with the paraneoplastic Doege–Potter syndrome, which is caused by<unk>  production of IGF-2.
Solitary fibrous tumor
Meningioma
Myxoid cyst
Peripheral ossifying fibroma
Collagenous fibroma
Pleomorphic fibroma
Ossifying fibromyxoid tumour
Aggressive fibromatosis