Solitary Fibrous Tumor of the Orbit: A Clinicopathologic Study of Two Cases With Review of the Literature

Abstract

Background/Aim: Orbital solitary fibrous tumor (SFT) is a rare lesion among orbital tumors, which can be misdiagnosed as another mesenchymal tumor. In this study we report two cases of orbital SFT, focusing on the imaging and pathological findings of the vascular structure inside the tumor. Case Report: A 26-year-old woman and 43-year-old man presented with orbital SFT. The pathological findings revealed a patternless growth pattern of the tumor cells and hemangiopericytoma-like vascularity as well as thickened, dilated blood vessels within the tumor tissue. Tumor cells revealed a diffuse strong positivity for cluster of differentiation 34 (CD34) and signal transducer and activator of transcription 6 (STAT6) in both cases, while Bcell lymphoma 2 (bcl-2) and CD99 were positive in one case. Characteristic findings within the tumor were the arterial components, where a variety of STAT6, CD99 and bcl-2positive smooth muscle cells were intermingled. Conclusion: Histologically, the tumor tissues might be characterized by not only conventional hemangiopericytoma-like vasculature but also dilated arterial vessels, which were shown to be part of the tumor components.Solitary fibrous tumor (SFT), a rare spindle-cell tumor, commonly arises from the pleura (1) but may also occur in extrapleural sites (2-5). Orbital SFT is a rare lesion and about 90 cases have been reported in the literature to date (6, 7). This tumor is likely to simulate other mesenchymal tumors such as fibrous histiocytoma, liposarcoma, synovial sarcoma, and neurofibroma. Since SFT is rich in feeding arteries, preoperative clinical diagnosis is important in assessing the likelihood of intraoperative bleeding (8), and total tumor resection is recommended (9). However, histopathological findings of the feeding vessels in SFT remain unknown. In this study, we report two cases of orbital SFT, focusing on the imaging and pathological findings of the vascular structure inside the tumor. The institutional review board in Hokkaido University and Teine Keijinkai Hospital waived the ethical assessment of the clinical study because of case reports. This study adhered to the principles of the Declaration of Helsinki. Case ReportCase 1. A 26-year-old woman presented with progressive and painless lower eyelid swelling for 2 months. An elastic hard, non-tender and non-pulsatile mass was palpable in the lower eyelid. Computed tomography revealed a well-defined heterogeneous mass along the lower wall of the right orbit (Figure 1A). Magnetic resonance imaging (MRI) demonstrated an orbital lesion with an isointense signal on T1-weighted images (T1WI) (Figure 1B) and a hyperintense signal on T2weighted images (T2WI) (Figure 1C). Postcontrast T1WI revealed a strong enhancement of the lesion that contained a linear flow void-like hypointensity (Figure 1D, arrow). Surgical excision was performed. There was bleeding from the 3649 This article is freely accessible online.

Orbital Solitary Fibrous Tumor: Four Case Reports—Clinical and Histopathological Features

“…For this reason, the treatment of choice for SFT, HPC, and FH is a complete excision of the tumor and careful follow-up in order to prevent recurrences and progression. In HPC, the histopathological features do not always correlate with biological behavior, including malignant potential [ 9 , 21 ]. Our first case was treated with complete surgical excision of the tumor.…”

Ocular transcription factor E3‐associated perivascular epithelioid cell tumor in children: Case report and review of the literature

“…cases. 13 NONO-TFE3, PRCC-TFE3, SFPQP-TFE3, 14 DVL2-TFE3, 15 and RBMX-TFE316 are examples of fusion genes with various histological presentations. In ocular PEComa, only the first two have been reported.…”

Head and neck solitary fibrous tumors: A review of the National Cancer Database

“…In the head and neck, cases of SFT are classically known to be indolent with symptoms resulting from the compression of nearby anatomical structures. The most common anatomy affected in this region is the oral cavity 5 ; however, SFT has also been reported in the orbit, 6 sinonasal tract, 7 larynx, 8 salivary glands, 9 and thyroid 10 . Histologically, head and neck SFT shares similar morphological features as those of pleural SFT, particularly a patternless distribution of oval and spindle shaped cells in a variable collagen stroma 11 .…”