Intraosseous “Lipoma” of the Calcaneus Developing in an Intraosseous Ganglion Cyst

2017-06-20 17:14:23

Category: Musculoskeletal Imaging, Region: Lower extremity-Ankle joint, Plane: Axial

Intraosseous lipomas are rare primary bone tumors, most common to the calcaneus. There are several proposed theories of the natural etiology of intraosseous lipomas; however, all lack definitive support. In this report, an 18 year old man presented with radiologic evidence of a simple bone cyst of the calcaneus. Over a four year period, the patient was followed with interval MR imaging. The cyst demonstrated progressive development of peripheral intralesional fat with a final MR imaging features characteristic of an intraosseous lipoma. To our knowledge this is the first longitudinal study to demonstrate gradual peripheral fat deposition developing within an intraosseous ganglion cyst. The purpose of this case presentation is to illustrate one potential etiology of intraosseous lipomas of the calcaneus and provide a review of the literature. This is not a case report of an intraosseous lipoma, nor is it a case report of an intraosseous cyst. Rather, this presentation of two cases with serial MRI image challenges the etiology of these calcaneal lesions as true "lipomas."