LETTER TO EDITOR
Year : 2008 | Volume
: 51 | Issue : 3 | Page : 453--455
Solitary fibrous tumor of the orbit
B Mukherjee1, J Biswas2,
1 Department of Orbit, Oculoplasty and Trauma, Medical Research Foundation, Sankara Nethralaya, 18, College Road, Chennai - 600 006, India
2 Department of Uvea and Ophthalmic Pathology, Medical Research Foundation, Sankara Nethralaya, 18, College Road, Chennai - 600 006, India
Department of Orbit, Oculoplasty and Trauma, Medical Research Foundation, Sankara Nethralaya, 18, College Road, Chennai - 600 006
|How to cite this article:|
Mukherjee B, Biswas J. Solitary fibrous tumor of the orbit.Indian J Pathol Microbiol 2008;51:453-455
|How to cite this URL:|
Mukherjee B, Biswas J. Solitary fibrous tumor of the orbit. Indian J Pathol Microbiol [serial online] 2008 [cited 2020 Sep 23 ];51:453-455
Available from: http://www.ijpmonline.org/text.asp?2008/51/3/453/42530
Solitary fibrous tumor (SFT) is a rare spindle cell neoplasm. We report a rare case of solitary fibrous tumor of the orbit with immunohistochemical confirmation.
A 19-year-old female presented with a history of painless protrusion of the right eye of over 1-year duration. There was a down and out dystopia of the right globe. The anterior segment examination of both eyes was otherwise normal. Fundus examination revealed mild disc edema in the right eye. There was a firm lobulated mass felt along the superomedial right orbit. B scan Ultrasonography showed a large mass in superonasal quadrant of the right orbit with high surface reflectivity. CT scan revealed a well-circumscribed oval, extraconal lesion in the superonasal orbit, displacing the globe laterally and inferiorly, extending up to the midorbit level. She underwent medial orbitotomy with complete removal of the mass. The postoperative period was uneventful, with complete resolution of proptosis.
Gross examination revealed a tan-colored mass measuring 22 mm × 20 mm. Microscopically, the tumor was composed of fibro-collagenous tissue and spindle cells arranged in a fascicular fashion around thick collagen fibers with occasional myxoid stroma [Figure 1]. Numerous vascular channels with a pericytomatous arrangement were seen [Figure 2]. Immunohistochemically, the tumor cells were vimentin [Figure 3] and CD34 [Figure 4] positive, but negative for cytokeratin, CD31 and S100, supporting the diagnosis of solitary fibrous tumor.
The first orbital SFTs were described by Dorfman et al and Westra et al, in 1994. , It is a tumor of mesenchymal origin that usually arises in the pleura. SFT in other extra-pleural sites, including the lung, mediastinum, peritoneum, upper respiratory tract, thyroid and liver has been increasingly reported in recent years. About 50 cases of orbital SFT have been reported in the literature till date. SFT was differentiated from other spindle cell tumors by Westra et al , on the basis of light microscopic features like thick bands of collagen, alternating hypo and hyper cellular areas, keloid-like hyalinization (described as pattern-less pattern) and a hemangiopericytoma-like pattern of vascularity.
The histopathologic differential diagnosis of SFT includes giant cell angiofibroma, fibrous histiocytoma, hemangiopericytoma, peripheral nerve sheath tumor, fibromyxoid sarcoma and other rare mesenchymal tumors.
SFT is immunoreactive for mesenchymal markers such as vimentin, but negative for desmin, epithelial marker (cytokeratin), vascular marker (factorVIII related antigen), neural markers (S-100 protein), muscle specific actin and smooth muscle actin.
Immunoreactivity with the marker CD 34 is present in 75-100% of cases. Although giant cell angiofibroma shares an identical immunostaining pattern, multinucleated giant cells are not usually seen in SFT.
SFT usually behaves in a benign fashion and do not metastasize. Only one case of malignant SFT has been reported so far.  However, local recurrences are possible and usually follows an incomplete initial excision. Even histopathologically, benign tumors ( 
Hence, en bloc surgical removal with long-term follow-up remains the mainstay of treatment in these patients as well as the most important prognostic factor. 
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