To investigate the diagnostic features of ultrasonography and pathology of solitary fibrous tumors (SFT).

Contrast-enhanced ultrasonography and pathology data of 6 patients with solitary fibrous tumor (SFT) confirmed by surgery and pathology in Qingdao Municipal Hospital from January 2015 to December 2019 were retrospectively analyzed, and the diagnostic characteristics were summarized.

Three cases were male, and three cases were female in six patients. The ages range from 32 to 65. One case was located in the abdominal wall, 1 case was located in the foot dorsum, 1 case was located in the eye socket, 2 cases were located in the chest wall and 1 case was located in mammary gland. The two-dimensional ultrasonographic manifestations of 6 cases of SFT were hypoechoic, moderate or mixed echogenic masses with clear or unclear boundaries and smooth edges. 4 cases were oval, 2 cases were round, 2 cases had non-uniform echo with liquefaction, 4 cases had relatively uniform echo, 4 cases had abundant branching blood flow signals, and the vascular resistance was small. Contrast-enhanced ultrasonography showed high enhancement of uniformity or unevenness in the arterial phase, 2 cases showed increased lesion enhancement range compared with conventional ultrasound, 4 cases showed no significant increase in lesion enhancement range compared with conventional ultrasound, and there was no significant clearance in the delayed phase, showing slightly higher enhancement. All tumors of the 6 cases were surgically removed, 4 cases had complete capsule, 2 cases had unclear boundary with surrounding tissue, 4 cases had abundant vascular supply, 2 cases had necrotic liquefaction zone, 4 cases had ductile, 2 cases had medium texture. Postoperative routine HE staining: source of mesenchymal tissue tumors and tumor cells showed spindle type, around blood vessel growth, a spiral or funicular, cell clusters alternating with sparse area distribution of tumor cell distribution. Unequal thickness and red color of collagen fibers and abundant dendritic parenchyma vessels were found in the interstitium. Four cases of nuclear had mild atypia and few mitotic, while 2 cases of nuclear had moderate atypia and visible mitotic. Immunohistochemical results: CD34 positive (4/6), Bcl-2 positive (5/6), Vimentin positive (5/6), CD99 positive (6/6), SMA positive (4/6). S100 negative (6/6), consistented with the the diagnosis of SFT.

Contrast-enhanced ultrasonography and pathology of SFT have certain characteristics, which are helpful for their diagnosis.