A 46-year-old female with extra-articular tenosynovial chondromatosis of the middle finger. Plain radiographs of the finger show an osseous nodule in the middle finger (a). The lesion has heterogeneous low- to high-signal intensity on T1-weighted (b), T2-weighted (c), and T2-weighted fat-suppression (d) images. A photograph of the resected specimen (e). Images of H&E histology sections of cartilaginous nodules with ossification and bone marrow-like fat tissue (f). Original magnification of panel f: x10 (top) and x40 (bottom).