Disease Definition: Solitary fibrous tumor (SFT), also known as fibrous tumor of the pleura, is a rare mesenchymal tumor originating in the pleura or at virtually any site in the soft tissue including seminal vesicle. Approximately 78% to 88% of SFT's are benign and 12% to 22% are malignant. It is a heterogeneous group of rare spindle-cell tumors that include benign and malignant neoplasms. Their cell of origin is still debated. SFT is preferred by most pathologists as a better term than “hemangiopericytoma” that gathers numerous unrelated entities and is presently only employed by neuropathologists. We focus the present paper on the forms of this family of tumors occurring in adult patients. There are 3 typical primary locations: pleural, meningeal and extrathoracic soft tissue.
Disease Symptoms: Patients present with proptosis and possibly ptosis, eyelid swelling, tearing, diplopia or decreased vision. Malignant infiltrating lesions can sometimes cause pain.
Disease Treatment: Because even benign-appearing solitary fibrous tumors (SFTs) can be locally recurrent and metastatic, wide resection of both benign and malignant SFTs is recommended. Preoperative vascular studies and arterial embolization should be considered because of the known bleeding risk with resection. Careful exclusion of other diagnoses (eg, synovial sarcoma) is important. Because of the favorable outcome with SFTs, it may be possible to avoid limb-threatening and deforming operations. No evidence suggests that adjuvant chemotherapy is beneficial. If the SFTR appears malignant histologically, adjuvant radiation therapy may be considered. Long-term follow-up is recommended because local and distant relapse is possible, even with benign-appearing tumors.
Statistics: Solitary fibrous tumor (SFT) is an uncommon spindle-cell neoplasm that most often involves the pleura, rarely occurring in extra-thoracic locations. Twenty-six cases of SFT arising in the thyroid gland have been described. We report a case of a 60-year-old woman presenting an 8-month history of enlargement of the neck associated with dysphagia. The patient underwent a right hemithyroidectomy and SFT of the thyroid was diagnosed. Immunohistochemistry showed positivity for CD34 marker, and the high number of mitoses and the presence of cellular atypia suggested that the tumor was malignant. To our knowledge, this is the second case of malignant SFT of the thyroid gland ever reported. Due to the rarity of these tumors, the indication of adjuvant therapy and prognosis are uncertain. Long-term follow-up after surgical resection seems to be advisable.