Yonago Acta medica 2008;51:77–82
Solitary Fibrous Tumor of the Thigh: A Patient Report
Kensaku Yamaga, Takeshi Minamizaki*, Mari Osaki*, Kohei Shomori, Naoko Ishiguro†, Haruhiko Yoshida and Hisao Ito
Division of Organ Pathology, Department of Microbiology and Pathology, School of Medicine, Tottori University Faculty of Medicine, Yonago 683-8503, *Department of Orthopedic Surgery, Yonago Medical Center, National Hospital Organization, Yonago 683-8518 and †Department of Pathobiological Science and Technology, School of Health Science, Tottori University Faculty of Medicine, Yonago 683-8503 Japan
We report a rare case of solitary fibrous tumor (SFT) within the thigh muscle. A 37-year-old woman noticed a painless mass in her left thigh, which had gradually enlarged. Computed tomography (CT) showed an intramuscular tumor and enhanced CT showed strong enhancement within the lesion. Magnetic resonance imaging revealed that the tumor measured 13.1 × 7.3 × 2.3 cm and was located within the sartorius muscle, with a clearly defined margin. Malignancy was suspected and the tumor was surgically resected. The tumor was characterized by a well-circumscribed lesion, and was composed of bland or short spindle cells, which were patternless, with scattered thick collagen bundles, and variably gaping thin- or hyalin-walled blood vessels. Immunohistochemically, the tumor cells were positive for vimentin, CD34, CD99 and focally, bcl-2. The tumor was subsequently diagnosed as an extrapleural SFT, which is classified into an intermediated (rarely metastasizing) category. Extrapleural SFT should be considered in the evaluation of soft tissue tumors in the extremities, although it may be rare.
Key words: extremity; soft tissue tumor; solitary fibrous tumor
