The MR and CT studies show a lobulated fatty lesion in head-neck of the left 12th rib. The macroscopic contents of fat with sparse soft tissue intensity/density are similar in appearance to that of soft-tissue angiolipomas.

The differential diagnosis could include:

• metastasis of lipid-containing neoplasm: may give the appearance of a benign/non-aggressive lesion
• angiolipoma: subcutaneous, adolescent to young adult. Few case reports of intraosseous angiolipoma ^1-4
• liposarcoma: in soft tissues (e.g. retroperitoneum)
• hemangioma: bony trabeculae
• solid variant of aneurysmal bone cyst (giant cell reparative granuloma): solid-cystic, in appendicular long bones
• site of extramedullary hematopoiesis: extraosseous paraspinal, in the presence of a myeloproliferative disorder or hemoglobinopathy