A Black Hole in a Bone — Intraosseous Lipoma

Abstract

Intraosseous lipoma is an extremely rarely diagnosed benign bone tumor. In most cases diagnostic imaging techniques, namely computed tomography (CT) and magnetic resonance imaging (MRI) are sufficient to reach a diagnosis, which in some cases is confirmed by postsurgical or postmortem histological examination. We describe 2 cases of intraosseous lipoma that were identified by practising rheumatologists at our rheumatology clinic. A 38-year-old man presented with pain in his right foot, ankle, knee, and first metatarsophalangeal joint. His history featured trauma-induced fractures of the left ankle and the right 6th rib. He did not recall any recent infection, travel, exertion, or other illness. Examination including musculoskeletal examination yielded no significant findings. Laboratory tests including metabolic panel and parathyroid hormone values were normal. Conventional radiographs of the right ankle and foot revealed a round, translucent, cystic lesion in the right calcaneal diaphysis in the trabecular bone, with areas of calcification (Figure 1a). CT scan of the lesion showed complete resorption of bone within the lesion, with the remaining tissue showing a fat …