Presentation
Limping, unable to weight bear and pain right knee for two months
Patient Data
AP and lateral radiographs of the right knee show an eccentric expansile radiolucent geographic lesion with thin sclerotic borders, internal trabeculations and a narrow zone of transition in the distal femoral metaphysis. There is no osteoid or chondroid matrix, cortical destruction, aggressive periosteal reaction or soft tissue component.It extends to the growth plate and there is a modelling deformity of the distal femur.
MR imaging reveals the lesion to be hyperintense on T1 and hyperintense on T2 with a hypointense rim. There is no enhancement on contrast and suppression on fat saturation sequence. Growth plate involvement is confirmed on MR.
Case Discussion
This case illustrates the typical imaging features of an Intraosseous lipoma both on conventional and MR imaging. Recognition of a bone lesion as an intraosseous lipoma can usually be regarded as an endpoint to an investigation unless complicated. Biopsy and surgery can be avoided in the majority of patients.