Solitary fibrous tumor (SFT), also known as fibrous tumor of the pleura, is a rare

mesenchymal Mesenchyme () is a type of loosely organized animal embryonic connective tissue of undifferentiated cells that give rise to most tissues, such as skin, blood or bone. The interactions between mesenchyme and epithelium help to form nearly every o ...

tumor A neoplasm () is a type of abnormal and excessive growth of tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tissue, and persists ...

originating in the

pleura The pulmonary pleurae (''sing.'' pleura) are the two opposing layers of serous membrane overlying the lungs and the inside of the surrounding chest walls. The inner pleura, called the visceral pleura, covers the surface of each lung and dips bet ...

Travis WD, Brambilla E, Muller-Hermelink HK, Harris CC (Eds.): World Health Organization Classification of Tumours. Pathology and Genetics of Tumours of the Lung, Pleura, Thymus and Heart. IARC Press: Lyon 2004. or at virtually any site in the soft tissue including seminal vesicle. Approximately 78% to 88% of SFT's are

benign Malignancy () is the tendency of a medical condition to become progressively worse. Malignancy is most familiar as a characterization of cancer. A ''malignant'' tumor contrasts with a non-cancerous benign tumor, ''benign'' tumor in that a malign ...

and 12% to 22% are

malignant Malignancy () is the tendency of a medical condition to become progressively worse. Malignancy is most familiar as a characterization of cancer. A ''malignant'' tumor contrasts with a non-cancerous ''benign'' tumor in that a malignancy is not s ...

.Robinson LA. Solitary fibrous tumor of the pleura. Cancer Control 2006;13:264-9. The World Health Organization (2020) classified SET as specific type of tumor in the category of malignant

fibroblastic and myofibroblastic tumors Fibroblastic and myofibroblastic tumors (FMTs) develop from the mesenchymal stem cells which differentiate into fibroblasts (the most common cell type in connective tissue) and/or the myocytes/myoblasts that differentiate into muscle cells. FMTs ...

Signs and symptoms

About 80% of pleural SFTs originate in the visceral pleura, while 20% arise from parietal pleura.Briselli M, Mark EJ, Dickersin GR. Solitary fibrous tumors of the pleura: eight new cases and review of 360 cases in the literature" ''Cancer'' 1981;47:2678-89. Although they are often very large tumors (up to 40 cm. in diameter), over half are

asymptomatic In medicine, any disease is classified asymptomatic if a patient tests as carrier for a disease or infection but experiences no symptoms. Whenever a medical condition fails to show noticeable symptoms after a diagnosis it might be considered asy ...

at diagnosis. While some researchers have proposed that a SFT occupying at least 40% of the affected hemithorax be considered a "giant solitary fibrous tumor",Pinedo-Onofre JA, Robles-Pérez E, Peña-Mirabal ES, Hernández-Carrillo JA, Téllez-Becerra JL. iant solitary fibrous tumor of the pleura.Cir Cir 2010;78:31-43. rticle in Spanish no such "giant" variant has yet been recognized within the most widely used pleural tumor classification scheme. Some SFTs are associated with the paraneoplastic

Doege–Potter syndrome Doege–Potter syndrome (DPS) is a paraneoplastic syndrome in which hypoglycemia is associated with solitary fibrous tumors. The hypoglycemia is the result of the tumors producing insulin-like growth factor 2. The syndrome was first described i ...

, which is caused by tumor production of

IGF-2 Insulin-like growth factor 2 (IGF-2) is one of three protein hormones that share structural similarity to insulin. The MeSH definition reads: "A well-characterized neutral peptide believed to be secreted by the liver and to circulate in the blo ...

Pathophysiology

Recurrent somatic fusions of the two genes, NGFI-A–binding protein 2 (

NAB2 NGFI-A-binding protein 2 also known as EGR-1-binding protein 2 or melanoma-associated delayed early response protein (MADER) is a protein that in humans is encoded by the ''NAB2'' gene. Function This gene encodes a member of the family of NGFI-A ...

) and

STAT6 Signal transducer and activator of transcription 6 (STAT6) is a transcription factor that belongs to the Signal Transducer and Activator of Transcription (STAT) family of proteins. The proteins of STAT family transmit signals from a receptor com ...

, located at chromosomal region 12q13, have been identified in solitary fibrous tumors. Chest radiograph showing fibrous tumor of the pleura

Treatment

The treatment of choice for both benign and malignant SFT is complete ''en bloc'' surgical resection.

Prognosis

Prognosis in benign SFTs is excellent. About 8% will recur after first resection, with the recurrence usually cured after additional surgery. The prognosis in malignant SFTs is much more guarded. Approximately 63% of patients will have a recurrence of their tumor, of which more than half will succumb to disease progression within 2 years. Adjuvant chemotherapy and/or radiotherapy in malignant SFT remains controversial.

History

SFT was first mentioned in the scientific literature by Wagner.Wagner E. Das tuberkelahnliche lymphadenom (der cytogene oder reticulirte tuberkel). Arch Heilk (Leipig). 1870;11:497.> The first discussion of its clinical and pathological properties was by Klemperer and Rabin.de Perrot M, Fischer S, Brundler MA, et al. Solitary fibrous tumors of the pleura. Ann Thorac Surg. 2002;74:285-293. SFTs have also been known as

hemangiopericytoma A hemangiopericytoma is a type of soft-tissue sarcoma that originates in the pericytes in the walls of capillaries. When inside the nervous system, although not strictly a meningioma tumor, it is a meningeal tumor with a special aggressive behavior ...

s although this term has now been discontinued from WHO tumor classifications. Over the years pleural SFTs acquired a number of synonyms, including localized fibrous tumor, benign mesothelioma, localized fibrous mesothelioma, submesothelial fibroma, and pleural fibroma. The use of names that include ‘mesothelioma’ for this tumor is discouraged because of potential confusion with diffuse malignant mesothelioma, a much more serious disease.

Additional images

File:Gross pathology of an atypical solitary fibrous tumor.png, Gross pathology of an atypical solitary fibrous tumor, evidenced by some deeply yellow necrotic areas Image:Solitary fibrous tumour low mag.jpg, Solitary fibrous tumor - low magnification.

H&E stain Hematoxylin and eosin stain ( or haematoxylin and eosin stain or hematoxylin-eosin stain; often abbreviated as H&E stain or HE stain) is one of the principal tissue stains used in histology. It is the most widely used stain in medical diagnos ...

. Image:Solitary fibrous tumour high mag.jpg, Solitary fibrous tumor - high magnification. H&E stain.

References

External links

World Health Organization Classification of Tumours. Pathology and Genetics of Tumours of the Lung, Pleura, Thymus and Heart. (Download Page) {{DEFAULTSORT:Solitary Fibrous Tumor Pleura neoplasia