Fig. 1

Radiological and pathological findings of case 1 (a), (b) CR showed an osteogenic lesion similar to that on sagittal CT (c) on bone windows through the femur. (d) and (e) MRI demonstrated an isointense lesion to muscle tissue with a low signal intensity centre on T1-weighted images and a heterogeneous isointense to hyperintense lesion on T2-weighted images. (f) After contrast administration, the lesion showed heterogeneous peripheral enhancement with a foci of low signal intensity centrally on post-contrast images. (g) Six months after surgery, nodules with calcification and ossification accompanied by pleural effusion were found in her lung. (h) and (i) Haematoxylin-eosin staining of resected specimens showed loose aggregates of cells in a highly myxoid stroma background and segregated into lobules by the fibrovascular septa; however, under high-power microscopy, the presence of osteoid production directly by the tumour cells and nuclear abnormalities were found