Somatic and visceral solitary fibrous tumors in the abdomen and pelvis: cross-sectional imaging spectrum

Our plain-English summary of Somatic and visceral solitary fibrous tumors in the abdomen and pelvis: cross-sectional imaging spectrum, by A.K. Shanbhogue, S.R. Prasad, N. Takahashi, et al (Radiographics, 2011).

The study

• Authors: A.K. Shanbhogue, S.R. Prasad, N. Takahashi, R. Vikram, A. Zaheer, K. Sandrasegaran
• Journal: Radiographics
• Published: 2011;31(2):393-408
• Type of article: Review
• Cited by: 73 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Solitary fibrous tumors (SFTs) are a unique group of mesenchymal neoplasms of fibroblastic or myofibroblastic origin. These tumors were originally described as "benign fibrous mesotheliomas" of the pleural cavity and were erroneously thought to be confined to the serosal surfaces (due to a putative mesothelial or submesothelial origin). It is now established that SFTs are ubiquitous neoplasms with both pleural and extrapleural distribution. Extrapleural SFTs commonly occur in middle-aged adults and manifest as asymptomatic, slow-growing, large tumors. Fewer than 5% of patients with SFTs present with symptomatic hypoglycemia. SFTs are histopathologically diverse with a variable admixture of fibroblasts or myofibroblasts, numerous thin-walled vessels, and dense fibrosis. Tumors previously categorized as hemangiopericytomas are now considered cellular variants of SFTs. At imaging, SFTs demonstrate remarkable heterogeneity, with variable degrees of enhancement, necrosis, or hemorrhage. Although most extrapleural SFTs have a benign clinical course, 10%-15% of these tumors demonstrate aggressive behavior in the form of recurrence or malignancy.

© RSNA, 2011.

In plain English

This article was a review, not a new study. Radiologists reviewed published reports on solitary fibrous tumors (SFTs) in the abdomen and pelvis and showed CT and MR images from individual patients. SFTs are rare tumors of fibroblastic or myofibroblastic origin. The authors explained that SFTs were first described as "benign fibrous mesotheliomas" of the pleura, but that this mesothelial origin is now considered wrong. The article did not discuss asbestos or any other exposure as a cause. Drawing on earlier reports, the authors stated that fewer than 5% of patients present with low blood sugar (hypoglycemia). They also stated that most SFTs outside the pleura behave benignly, but 10%–15% recur or are malignant. They described tumors in many abdominal and pelvic sites. Imaging alone often cannot tell SFTs from other tumors, including malignant mesothelioma. Tissue examination after surgery or, in some cases, biopsy is needed to confirm the diagnosis. The authors concluded that knowing the typical imaging features helps suggest the diagnosis. They also stated that tumors first judged benign under the microscope still need long-term follow-up, because some later spread.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: narrative review of published literature, illustrated with imaging from individual patients
• Who was studied: Published reports of solitary fibrous tumors of the abdomen and pelvis, plus illustrative images from individual patients (for example, a 71-year-old woman with a liver SFT)
• Exposure: None studied; the article does not discuss asbestos or any other exposure
• Main results:
  • The authors stated that SFTs were originally described as "benign fibrous mesotheliomas" of the pleura, and that this view of their origin is now considered erroneous
  • Citing prior literature, the authors stated that a small subset of SFTs (fewer than 5%) present with hypoglycemia
  • The authors stated that most extrapleural SFTs have a benign course, but 10%–15% show aggressive behavior (recurrence or malignancy)
  • Malignant mesothelioma was listed among the tumors that can look like a retroperitoneal SFT on imaging
  • The authors stated that surgical excision and tissue analysis are needed to confirm the diagnosis and to tell benign from malignant tumors
  • For prostatic SFTs, the authors stated that either surgical excision or transrectal biopsy, followed by tissue examination, is needed to confirm the diagnosis
  • Citing prior studies, the authors noted that some SFTs first classified as benign on tissue examination were later found to have metastases, so long-term follow-up is needed even when the tumor is histologically benign at initial diagnosis
• The authors' conclusion: The authors concluded that better awareness of where SFTs occur and of their classic imaging features will help suggest the diagnosis, and that imaging aids preoperative mapping and surveillance after treatment
• Limitations the authors state:
  • The authors noted that reported data showing prostatic SFTs to be benign may be misleading, because there are few cases and some tumors were incompletely resected
  • The authors noted that little cytogenetic data exist for SFTs outside the meninges

Topics

Medical terms in this study, explained in our Lexicon: Solitary Fibrous Tumor, Neoplasm, Mesothelioma, Pleural Cavity, Serosal Surface, Fibroblast, Fibrosis, Necrosis.

Related studies

• Atypical solitary fibrous tumor of the nose and maxillary sinus — I. Papadakis, E. Koudounarakis, et al. (2013)
• Localized fibrous nodular mesothelioma of the pelvis — M.J. Schutz, R. Fink (1998)
• Nuclear expression of STAT6 distinguishes solitary fibrous tumor from histologic mimics — L.A. Doyle, M. Vivero, et al. (2014)
• Value of D2-40 in the differential diagnosis of pleural neoplasms with emphasis on its positivity in solitary fibrous tumor — Y. Hu, Q. Yang, et al. (2010)
• Malignant mesothelioma presenting as a giant chest, abdominal and pelvic wall mass — Z.H. Shao, X.L. Gao, et al. (2011)
• Solitary fibrous tumor of the orbit: CT and pathologic correlation — S. Festa, H.J. Lee, et al. (1999)

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