Vorachai SirikulchayanontaSuphaneewan JaovisidhMahidol UniversityFaculty of Medicine, Ramathibodi Hospital, Mahidol University2018-07-122018-07-122008-02-01Journal of the Medical Association of Thailand. Vol.91, No.2 (2008), 244-24801252208012522082-s2.0-40949100861https://repository.li.mahidol.ac.th/handle/123456789/19766The authors present a case of a 42-year-old female who developed a leiomyosarcoma of the right proximal tibia that appeared radiologically similar to a giant cell tumor. Histology revealed spindle cells running in whorl-like fashion with focal atypia and low mitotic figures. The immuno-stains revealed positive reactivity for alpha-smooth muscle (SMA), muscle actin and cytokeratin (AE1/AE3). The authors rendered a diagnosis of low-grade leiomyosarcoma of bone. The lesion was considered a primary lesion since the patient did not have other leiomyomatous tumors. The MRI showed hypo- to iso- signal intensity on T1-weighted imaging and heterogeneous intensity on T2-weighted imaging. This was likely due to admixed fibrotic tissue in the lesion. The tumor cells were not positive for Ebstein-Barr virus by in-situ hybridization as seen in leiomyomatous tumors in immunodeficiency patients.Mahidol UniversityMedicineArticleSCOPUS