History

Solitary fibrous tumours, previously known as “benign mesotheliomas,” are rare mesenchymal tumours that were first described in the pleura by Lietaud in 1767 and later by Wagner in 1870. It was later characterized by Klemperer and Rabin in 1931. The further classification was completed by Briselli in 1981 and England in 1989.

SFT in the pleura was first described in 1931 and historically recognized by various different names, including benign mesothelioma, localized mesothelioma, solitary fibrous mesothelioma, pleural fibroma, submesothelial fibroma, subserosal fibroma, Lietaud's tumour or Wagner's tumour and localized fibrous tumour. SFT is now recognized to occur anywhere in the body, including soft tissue and viscera, albeit with a peculiar predilection for body cavity sites, including pleura, peritoneum, and meninges.

Hemangiopericytomas were first described in 1942 and initially thought to be a vascular neoplasm related to pericytes (smooth muscle perivascular cells). However, the diagnosis was largely descriptive, based upon a nonspecific, albeit characteristic, staghorn vascular pattern, and the term became a "wastebasket" diagnosis, which included a variety of unrelated benign and malignant entities.

The discovery of a shared, recurrent, and thus far unique gene fusion in SFT and tumours histologically identified as hemangiopericytoma has confirmed the identical nature of these tumours. At present, the term SFT is preferred and the use of the term "hemangiopericytoma" is discouraged in clinical practice. However, some neuropathologists still prefer the term hemangiopericytoma in reference to meningeal tumors to emphasize their aggressive behaviour compared with other SFT.

Initially, SFT was believed to affect only the pleura, mediastinum, and serosal surfaces. Hence the term “localized fibrous tumours of the pleura" was given to this tumour. But further development in the diagnostic techniques identified SFT masses subsequently in the head, neck, breast, abdomen, pelvis, and extremities, necessitating recategorization as solitary fibrous tumours. World Health Organization Classification of Tumors, revised solitary fibrous tumours, which were previously considered mesothelial and submesothelial lesions of the pleura, are now considered soft-tissue neoplasms of pluripotent fibroblastic or myofibroblastic origin that may arise anywhere throughout the body.