Giant Solitary Fibrous Tumor of Orbit

A review of solitary fibrous tumours of the orbit and ocular adnexa

Solitary fibrous tumour (SFT) is an uncommon spindle cell tumour of mesenchymal origin characterised by NAB2-STAT6 gene fusion. Although it was first described in the pleura, it can occur in connective tissue in any part of the body, but rarely presents in the orbit and ocular adnexa. SFT, which is part of the same disease spectrum as other fibroblastic tumours such as giant cell angiofibroma, haemangiopericytoma and fibrous histiocytoma, usually presents as a painless, slow-growing mass in any age group and generally follows a benign course, with a good prognosis after complete excision. However, malignant forms rarely occur. Even for benign tumours a more aggressive clinical behaviour is possible, with relentless infiltrative local growth, frequent recurrence following surgery, and malignant transformation with the potential for metastatic spread. Careful long-term follow-up is essential. The published literature on SFTs of the orbit and ocular adnexa is reviewed, and the aetiology, clinical presentation, epidemiology, radiological features, histopathology, immunohistochemistry, risk stratification, clinical management, and prognosis are discussed, reflecting on our own experience.

Solitary Fibrous Tumor of the Orbit: A Case Series With Clinicopathologic Correlation and Evaluation of STAT6 as a Diagnostic Marker

PURPOSE

To retrospectively describe the clinical characteristics, management, and outcomes of a series of patients with solitary fibrous tumor (SFT) of the orbit and to evaluate signal transducer and activator of transcription 6 (STAT6) as a diagnostic marker.

METHODS

Review of a retrospective, noncomparative, consecutive series of patients treated at a single institution with a histopathologic diagnosis of SFT. Demographic, clinical, and imaging data were collected, and paraffin-embedded tissue sections were stained to evaluate for the presence of STAT6 and other pertinent markers.

RESULTS

Twenty-one patients were identified. Most presented with painless progressive proptosis or eyelid swelling for less than 6 months. Imaging revealed well-circumscribed, firm, variably vascular contrast-enhancing lesions with low to medium reflectivity on ultrasound. Four tumors were histopathologically malignant. All tumors were primarily excised, and 1 patient required exenteration. Two patients were treated with adjuvant radiation therapy. Six patients had recurrent disease of which 3 underwent repeat excision, and 2 were observed. No metastatic disease or attributable deaths were observed. All lesions with available tissue stained positively for both CD34 and STAT6.

CONCLUSION

This is the largest single institution case series of orbital SFT with clinicopathologic correlation and the largest series to confirm the presence of STAT6 in orbital lesions. The management of SFT remains challenging due to unpredictable tumor behavior, and complete excision is the generally recommended treatment. It remains unclear whether a subset of asymptomatic patients with histopathologically benign disease can be durably observed without negative sequelae.

Orbit Solitary Fibrous Tumor: A Proposed Risk Prediction Model Based on a Case Series and Comprehensive Literature Review

Solitary fibrous tumors (SFTs) of the orbit are rare. In order to further characterize the clinical and pathologic features of solitary fibrous tumor arising at this anatomic site, 12 cases of orbital SFTs were analyzed in conjunction with a review of 263 cases reported from the English literature in order to develop a risk prediction model. SFTs of the orbit were equally distributed between males (n = 5) and females (n = 7) with a mean patient age of 46.8 years (median 44.5 years; range 18-76 years) at initial diagnosis. The patients typically presented with swelling or mass around the orbit, with proptosis (n = 10), ptosis (n = 5), and visual changes (n = 6). Tumors were orbital (n = 10) or upper eyelid (n = 2). Mean tumor size was 2.5 cm (median 2.6 cm). Microscopically, the tumors were characterized by cytologically bland spindle cells with patternless growth, hypocellular and hypercellular areas, variable amounts of collagen, and ectatic, branching blood vessels. By immunohistochemistry, all cases had a strong nuclear STAT6 expression. All patients were initially managed with excision or biopsy, three with presurgical embolization. The two patients with biopsy only had persistent disease (mean 37.2 months), but a third patient developed distant bone metastasis at 86.9 months. Overall mean follow-up was 73.1 months: 9 patients are alive or dead without disease (mean 77.9 months), two patients with persistent disease, and one patient with metastatic disease at last follow-up (102 months). Incorporating cases sufficiently reported in the literature, a risk prediction model based on age > 45 years, tumor size > 3 cm, tumor necrosis, mitoses of > 4/2 mm2, moderate to high cellularity, and moderate to severe pleomorphism allows for risk stratification for the development of local recurrence and distant metastasis. In conclusion, orbital SFTs are rare, but can be reliably diagnosed based on the presence of characteristic morphologic features and STAT6 immunohistochemistry. Orbital tumors tend to show a higher frequency of local recurrence than distant metastasis, which can be predicted by a risk stratification model unique to orbital tumors. With late disease common, long term clinical follow-up is recommended.

Orbital solitary fibrous tumor: a clinicopathologic study from a Chinese tertiary hospital with a literature review

Purpose

To report the clinical features, imaging manifestations, histopathology, and immunohistochemical features of several cases of orbital solitary fibrous tumors (SFTs) in a Chinese tertiary hospital, and to undertake a literature review of this rare disease.

Methods

A non-comparative retrospective review of clinical presentations, imaging manifestations, histopathology, and immunohistochemical features as well as the management and disease outcomes of patients with orbital SFT was conducted along with a review of orbital SFT cases in the literature.

Results

This study includes two male and two female patients, with an average age of 53 years. Common presentations among these patients included a palpable subcutaneous mass, swelling of the eyelid, proptosis, diplopia, and vision disturbance. Three patients (cases 2–4) underwent imaging scans. All patients had complete surgical excisions and the tissue was subjected to pathological analysis. One patient (Case 4) experienced a recurrence with malignant transformation and received a re-excision surgery and postoperative radiotherapy. All patients remain alive and well after a minimum follow-up of 12 months (range 12–34 months).

Conclusion

Despite its rare occurrence, we suggest that the possibility of orbital SFTs needs to be considered when a painless, slowly growing orbital mass is identified. Typical characteristic magnetic resonance imaging features of orbital SFTs are iso- or hypointense signals on T1 and T2-weighted images, with marked enhancement. A positive cluster of differentiation 34 (CD34) staining is an important diagnostic clue favoring SFT. Some orbital SFTs are infiltrating, aggressive, or recur with malignant transformation. Therefore, regular long-term follow-up after complete excision is mandatory.

A Rare Case of a Recurrent Giant Solitary Fibrous Tumor of the Ciliary Body of the Orbit

Solitary fibrous tumors (SFTs) are uncommon spindle-cell tumors of mesenchymal origin initially described in the pleura and subsequently in other extra-pleural sites. These tumors are categorized as tumors of 'intermediate malignancy' under the World Health Organization classification of soft tissue tumors. SFT was virtually non-existent or misdiagnosed until its characteristic features, particularly the strong and diffuse immuno-reactivity to CD 34 were described. Extra-pleural manifestations of SFT, particularly in the head and neck region are rare. Although a number of isolated case reports of orbital SFTs have been described ever since its initial description in 1994, cases of recurrent SFTs have been very few. Recurrences of these tumors following surgery are considered unusual and metastasis exceptional. We describe clinical presentation and the management challenges of recurrent giant orbital SFT in a 15-year old girl along with a brief review of literature.