Endocrine Abstracts

The solitary fibrous tumor is a rare spindle cell neoplasm, originally described in the pleural cavity. However, it can occur in other locations. SFTs that originate from the adrenal gland tissue are extremely rare. To date, only single cases have been described in the literature. We present a case of a 61-year-old Caucasian man with a SFT of the left adrenal gland. The patient was hospitalized in the internal medicine department due to paroxysmal hypertension (up to 190/100 mmHg) and an episode of syncope. An abdominal computed tomography scan was performed, in which a lobular, well-demarcated, 63×66×70 mm, intense post-contrast tumor was described in the left adrenal gland. The overall radiological picture was indicative of a pheochromocytoma. In hormonal tests, slightly elevated normetanephrine and 3-metoxytramine concentrations were found in 24-hour urine collection. Elevated hemoglobin, increased erythrocyte count, and elevated erythropoietin concentration were observed and the suspicion of polycythemia vera was raised. The patient required numerous bloodletting. Genetic tests did not show pathological variants in the JAK2 gene. The patient was qualified to left adrenalectomy. Pathomorphological examination revealed a SFT with a diameter of 5.5 cm made of a network of interconnecting vessels of different caliber (immunohistochemically: CD31+, CD34+) focally with small visible atypia of endothelial cells, between which bright CD99+ cells were visible, and in part ERG+, bcl2-. The proliferative activity of Ki67 was about 10%. In post-operative follow-up tests 24-hour urinary fractionated metanephrines concentration and the blood count results have returned to normal ranges. The patient remains under regular surveillance. SFTs are usually indolent tumors that do not give certain clinical manifestations. They are extremely rare tumors, which may present with various uncharacteristic symptoms and should be considered in the differential diagnosis of an incidentally discovered adrenal mass.