Giant solitary fibrous tumor of the orbit with aggressive behavior

Solitary fibrous tumor (SFT) is a rare spindle cell neoplasm that was initially described as a mesenchymal neoplasm in the pleura. SFT have subsequently been diagnosed in the pericardium, mediastinum, liver, breast, peritoneum, nasopharynx, paranasal sinuses, salivary gland, thyroid gland, and orbit. Histopathological and immunohistological features are crucial for a correct differential diagnosis, because the neoplastic cells of SFT express CD34, thus differentiating this tumor from other spindle cell neoplasms. Orbital SFTs usually present an indolent and benign course with unilateral painless proptosis, visual disturbance, palpable orbital mass, ocular mobility disturbance, hyperglobus or blepharoptosis from the secondary mass effect in the orbit. However, few cases have shown aggressive behavior with adjacent tissue invasion, recurrence after partial resection, or malignant transformation with metastasis.The purpose of this article is to present and discuss a case of orbital solitary fibrous tumor with aggressive behavior due to intracranial invasion.