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 ...
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 b ...
[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 in that a malignancy is not s ...
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.
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 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 b ...
.
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.
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
hemangiopericytomas 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.
See also
*
Hemangiopericytoma
*
Myopericytoma
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