Solitärer fibröser Tumor der Orbita: klinische, radiologische, histologische Merkmale und Differenzialdiagnose eines ungewöhnlichen Tumors

Solitary fibrous tumours (SFT) are mesenchymal neoplasias rarely found in the orbit. Due to their sharp delineation they are frequently mistaken for various benign neoplasma, such as cavernous hemangiomas, neurinomas and pleomorphic adenomas. We present two cases of SFT in the orbit and one in the lacrimal sac and discuss the radiological and histological differential diagnosis.Among 9 patients diagnosed and operated in our department between 2008 and 2010 with an orbital tumour, three had the histological diagnosis of a solitary fibrous tumour. In 5 cases an MRI scan was performed preoperatively, in 4 cases a CT scan.Histology showed 2 pleomorphic adenomas, 2 cavernous hemangiomas, 2 neurinomas and 3 SFT. All SFT were intraoperatively well circumscribed and enucleated, showing histologically incomplete resection. No further treatment was given. There is no recurrence in any of the patients in the follow up of an average of 10 months (range 1 - 30 months).SFT are rare mesenchymal tumours of the orbit. The radiological differential diagnosis is difficult and they can be mistaken for more common tumours. The SFT has a wide range of histological appearances. Long term clinical follow-up is mandatory in all cases of SFT.