A 43-year old man had a 2-cm soft tissue mass in the left lower leg that had doubled in size over the previous year. It was painless, hard, firm and deeply attached. Radiography ( Fig. 1), computed tomography ( Fig. 2) and gadoliniumenhanced magnetic resonance imaging (Fig. 3) were performed. Histopathology is also shown (Fig. 4). What is the diagnosis? We declare that the present research complies with the current laws of the country in which it was done (Spain), and that we have had full control of all primary data The diagnosis can be found at

Parosteal ossifying lipoma of the fibula: a case of benign lipomatous tumor showing gadolinium enhancement on MRI. Discussion Radiography shows a well-defined, calcified parosteal softtissue mass with fat density and calcification, apparently attached to the fibular cortex. Computed tomography shows both mass components (calcium and fat), well-delimited edges and the cortical relationship with a short narrow pedicle. Magnetic resonance imaging with a gadoliniumenhanced dynamic three-dimensional axial sequence shows inhomogeneity with fat-saturated low signal areas and foci of enhancement in non-fatty areas.