Intraosseous cholesterol granuloma of radius showing a lamellar structure on MR images: a case report.

We report a case of an intraosseous cholesterol granuloma in the radius showing a lamellar structure on MRI. T1-weighted imaging revealed a central area of mildly increased signal intensity with a surrounding low-intensity layer. On T2-weighted images, the central lesion demonstrated low-intensity signals, and the surrounding area exhibited a lamellar structure with three layers of high, low, and high intensity from the inside. On histological examination, the central area was found to consist of cholesterine crystals embedded in erythrocytes, and in the surrounding lamellar structure collagenous tissue may have provided the low signals, with vessel- and giant cell-enriched structures present at both the inner and outer margins, presumably evoking the high-intensity signals. The present lesion may have been formed by chronic hemorrhage into a preexisting simple bone cyst.