Solitary fibrous tumor: Histologic and immunohistochemical spectrum of benign variants presenting at different sites

Department of Pathology and Cell Biology, Jefferson Medical College of Thomas Jefferson University, Philadelphia, PA 19107, USA.
Human Pathlogy (Impact Factor: 2.77). 05/1995; 26(4):440-9. DOI: 10.1016/0046-8177(95)90147-7
Source: PubMed


Twenty-nine tumors (from 26 patients, including two with recurrent disease) diagnosed as solitary fibrous tumor (SFT) of the pleura (n = 23), mediastinum (n = 4), abdominal cavity (n = 1), and parotid gland (n = 1) were studied immunohistochemically. Three histologically malignant tumors showed areas of high cellularity and mitotic activity (more than 4 mitoses/10 high-power fields) with features resembling malignant fibrous histiocytoma, malignant hemangiopericytoma, or fibrosarcoma, together with areas typical of benign solitary fibrous tumor. Formaldehyde-fixed, paraffin-embedded tissues and avidin-biotin-complex immunostaining were used. All of the tumors showed vimentin positivity and did not stain for cytokeratin, glial fibrillary acidic protein, or muscle cell markers, except for focal desmin reactivity in seven tumors, mostly seen in frozen sections, and focal keratin reactivity in one histologically malignant tumor. The neoplastic cells were positive for CD34 and negative for CD31; these patterns also were seen in the three histologically malignant cases. In nine of the cases acetone-fixed frozen sections showed variable focal positivity for neurofilament proteins of 68 kd. We conclude that SFT is a neoplasm of fibroblasts/primitive mesenchymal cells with features of multidirectional differentiation. We also report the finding of a novel site for SFT, the parotid gland.

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    • "Thus, histologically, SFT can be confused with a variety of other soft tissue tumors, such as hemangiopericytoma and Schwannoma. Immunohistochemically, SFT can be differentiated from these tumors by their strong positivity for CD34 and vimentin, while being negative for CD31, cytokeratin, desmin, and the S-100 protein (4). "
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    ABSTRACT: Solitary fibrous tumor (SFT) is a well-known tumor composed of spindle cells found most commonly in the pleura. Recently, accounts of their rare occurrence at other sites, including the head and neck area, have been reported. The parapharyngeal space is a rare location even for head and neck SFTs, and thus, could be confused with a variety of other tumors that can originate in this area. Here, we report a case of SFT originating from the post-styloid parapharyngeal space and discuss the possible differential diagnosis on radiographic findings.
    Full-text · Article · Jul 2014
    • "Tumor cells are strongly positive for CD 34 in most cases.[4] However, its expression can be lost in high-grade tumors or tumors with repeated recurrence.[7] SFT may present with malignant behavior and local recurrence or metastasis. "
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    ABSTRACT: Solitary fibrous tumor (SFT) represents a spectrum of mesenchymal tumors, encompassing tumors previously termed hemangiopericytoma, as having intermediate biological potential. Though they can occur at any site, lower distal extremity is a rare site and recurrence in it is extremely rare. Behavior of SFT is unpredictable. Histomorphology and clinical follow-up have poor correlation. The most important single indicator of clinical outcome is complete excision of the tumor at the time of primary presentation. Tumors with positive margins require close follow-up for several years owing to the potential for late local recurrence.
    No preview · Article · Jul 2014
    • "Solitary fibrous tumors (SFT) are uncommon spindle cell tumors of mesenchymal origin that most often arises from the pleura but may also occur infrequently in various other sites including lungs, peritoneum, pericardium, kidneys, liver and rarely in the orbit.[1] Mesothelial differentiation as a probable source of its histogenesis has been questioned and replaced by a hypothesis of a fibroblastic differentiation instead.[2] Westra et al.,[3] described the characteristic immunohistochemical features of orbital SFT and found that it shows a strong and diffuse immunoreactivity to CD34. "
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    ABSTRACT: Orbital solitary fibrous tumor (SFT) is a rare tumor and orbits are a very uncommon site. It is mostly noted to arise from mesenchymal structures like pleura and peritoneum. The diagnosis of orbital SFT cannot be made with certainty on clinical or radiological evaluation alone and requires immunohistochemical studies for confirmation. Orbital SFT's usually show an indolent clinical course and a complete cure can usually be achieved with complete resection. We describe clinical presentations, radiological and operative findings, and pathological features of a patient with orbital SFT along with a brief review of literature.
    No preview · Article · Jun 2013 · Journal of research in medical sciences
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