Solitary fibrous tumor of the mediastinum

Our plain-English summary of Solitary fibrous tumor of the mediastinum, by N. Weidner (Ultrastructural Pathology, 1991).

The study

• Author: N. Weidner
• Journal: Ultrastructural Pathology
• Published: 1991;15(4-5):489-92
• Type of article: Case report
• Cited by: 28 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

A 62-year-old woman presented with an asymptomatic anterior mediastinal mass. Clinically considered to be a thymoma, the tumor was solid, firm, and composed of hypocellular dense collagen and cytologically bland, spindled fibroblastlike cells growing in a patternless pattern. There was no apparent connection to pleura or pericardium, yet the clinicopathologic features clearly fit with solitary fibrous tumor (SFT) of mediastinum. SFTs occur most commonly in pleura but have been reported in other locations, including the mediastinum, where aggressive behavior has been more common when these tumors are compared to those occurring in pleura. Although it is difficult to predict behavior for all cases of SFT occurring in the mediastinum by cytologic features alone, morphologic criteria for benign and malignant forms have been described. Roughly half the malignant forms will progress, yet the single most important indicator of clinical outcome is whether the tumor can be initially totally excised.

In plain English

This was a case report about one patient. A 62-year-old woman had a mass in the anterior mediastinum (the front of the chest between the lungs) that caused no symptoms and was found after a routine chest X-ray. The mass had no apparent connection to the pleura or pericardium, and it was completely and easily removed at surgery. Under the microscope it showed bland, spindle-shaped cells between dense bands of collagen. Mitotic figures (dividing cells) were rare, and there was no necrosis or cellular atypia. Electron microscopy showed features most consistent with a fibroblast, a type of connective tissue cell. The tumor cells stained positive for vimentin and negative for cytokeratin, CEA and Leu-M1. The author stated that thymoma and mesothelioma were ruled out because desmosomes, tonofilaments and keratin staining were absent. The author concluded that careful review of the clinical presentation, with attention to fibroblastlike features and the patternless growth pattern, should lead to the correct diagnosis in most cases of solitary fibrous tumor. The article did not mention asbestos and did not report the patient's later course.

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: case report, with the author's review of the clinical and pathologic features and differential diagnosis of solitary fibrous tumor
• Who was studied: one 62-year-old woman with a mass in the anterior mediastinum that caused no symptoms; the author worked at Brigham and Women's Hospital, Boston
• Exposure: The article does not mention asbestos or any other exposure.
• Main results:
  • The mass was found after a routine chest X-ray.
  • There was no apparent connection of the tumor to the pleura or pericardium.
  • At surgery the 5.0 x 5.4 x 2.0 cm mass was completely and easily removed.
  • Under the light microscope, mitotic figures were rare and there was no necrosis or cellular atypia.
  • Electron microscopy findings were most consistent with an inactive connective tissue cell (a fibroblast).
  • Tumor cells were positive for vimentin and negative for cytokeratin (AE1/3), CEA and Leu-M1.
  • The author stated that thymoma and mesothelioma were ruled out by the absence of desmosomes, tonofilaments and keratin immunoreactivity.
• The authors' conclusion: The author concluded that careful review of the clinical presentation, with attention to the fibroblastlike ultrastructural features and the patternless growth pattern, should lead to the correct diagnosis in most cases of solitary fibrous tumor.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Mesothelioma.

Medical terms in this study, explained in our Lexicon: Solitary Fibrous Tumor, Mediastinum, Collagen, Pleura, Pericardium.

Related studies

• Solitary fibrous tumor of the mediastinum. A report of 14 cases — G.B. Witkin, J. Rosai (1989)
• Nuclear expression of STAT6 distinguishes solitary fibrous tumor from histologic mimics — L.A. Doyle, M. Vivero, et al. (2014)
• A biphasic tumor of the mediastinum with features of synovial sarcoma. A report of four cases — G.B. Witkin, M. Miettinen, et al. (1989)
• Cytopathological features of solitary fibrous tumor of the pleura: a study of 5 cases — B. Weynand, P. Collard, et al. (1998)
• Solitary fibrous tumor of the liver: a clinicopathologic and immunohistochemical study of nine cases — C.A. Moran, K.G. Ishak, et al. (1998)
• RNA-binding protein LIN28 is a marker for primary extragonadal germ cell tumors: an immunohistochemical study of 131 cases — D. Cao, A. Liu, et al. (2011)

Browse more research in Ultrastructural Pathology, or return to medical research.