MR imaging features of tumors of the ankle and foot.

MR imaging is a useful technique in the work-up of neoplasms of the foot and ankle. Certain MR imaging traits may confer a specific diagnosis. For instance, the presence of fat in a homogeneous lesion would indicate a lipoma, while an intraarticular, poorly defined mass with low signal intensity on all pulse sequences is suspicious for pigmented villonodular synovitis. Most neoplasms, however, have no specific trademark MR features. In these cases, MR imaging is useful in imparting information that can assist in treatment and prognosis once a histologic diagnosis is made. For instance, MR imaging may help ascertain the presence and degree of bone marrow involvement, invasion of adjacent anatomical structures, and size of the lesion. MR imaging is an essential and effective modality for the preoperative staging of neoplasms of the foot and ankle.